Physiological role of FolD (methylenetetrahydrofolate dehydrogenase), FchA (methenyltetrahydrofolate cyclohydrolase) and Fhs (formyltetrahydrofolate synthetase) from Clostridium perfringens in a heterologous model of Escherichia coli

Most organisms possess bifunctional FolD 5,10-methylenetetrahydrofolate (5,10-CH2-THF) dehydrogenase-cyclohydrolase] to generate NADPH and 10-formyltetrandrofolate (10-CHO-THF) required in various metabolic steps. In addition, some organisms including Clostridium perfringens possess another protein, Fhs (formyltetrahydrofolate synthetase), to synthesize 10-CHO-THF. Here, we show that unlike the bifunctional FolD of Escherichia coli (Eco FolD), and contrary to its annotated bifunctional nature, C. perfringens FolD (Cpe FoID) is a monofunctional 5,10-CH2-THF dehydrogenase. The dehydrogenase activity of Cpe FoID is about five times more efficient than that of Eco FolD. The 5,10-methenyltetrahydrofolate (5,10-CH+-THF) cyclohydrolase activity in C. perfringens is provided by another protein, FchA (5,10-CH+-THF cyclohydrolase), whose cyclohydrolase activity is similar to 10 times more efficient than that of Eco FolD. Kinetic parameters for Cpe Fhs were also determined for utilization of all of its substrates. Both Cpe FoID and Cpe FchA are required to substitute for the single bifunctional FolD in E. coli. The simultaneous presence of Cpe FoID and Cpe FchA is also necessary to rescue an E coli folD deletion strain (harbouring Cpe Fhs support) for its formate and glycine auxotrophies, and to alleviate its susceptibility to trimethoprim (an antifolate drug) or UV light. The presence of the three clostridial proteins (FolD, FchA and Fhs) is required to maintain folate homeostasis in the cell.

Trans-dichlorooxovandium (IV) complex as a novel photoinducible DNA interstrand crosslinker for cancer therapy

Although DNA interstrand crosslinking (ICL) agents such as mitomycin C, cisplatin and psoralen serve as potent anticancer drugs, these agents are known to have dose-limiting toxic effects on normal cells. Moreover, tumor resistance to these agents has been reported. Here, we show that trans-dichlorooxovanadium (IV) complex of pyrenyl terpyridine (VDC) is a novel photoinducible DNA crosslinking agent. By a combination of in vitro and ex vivo experiments including plasmid-based assays, we find that VDC forms monoadducts on the DNA and can be activated by UV-A and visible light to generate DNA interstrand crosslinks. VDC efficiently activates Fanconi anemia (FA) pathway of DNA interstrand crosslink repair. Strikingly, photoinduction of VDC induces prolonged activation of cell cycle checkpoint and a high degree of cell death in homologous recombination (HR)/ICL repair defective cells. Moreover, VDC specifically targets cells that express pathological RAD51C mutants. These data imply that VDC can be potentially used for cancer therapy and suggest that tumors arising in patients with gene mutations in FA and HR repair pathway can be specifically targeted by a photoactivatable VDC.

Gasification of wood particles in a co-current packed bed: Experiments and model analysis

This study focuses on addressing the propagation front movement in a co-current downdraft gasification system. A detailed single particle modeling analysis extended to the packed bed reactor is used to compare with the experimental measurement as well those available in the literature. This model for biomass gasification systems considered pyrolysis process, gas phase volatile combustion, and heterogeneous char reactions along with gas phase reactions in the packed bed. The pyrolysis kinetics has a critical influence on the gasification process. The propagation front has been shown to increase with air mass flux, attains a peak and then decreases with further increase in air mass flux and finally approaches negative propagation rate. This indicates that front is receding, or no upward movement() bra her it is moving downward towards the char bed. The propagation rate correlates with mass flux as (m) over dot `'(0.883) during the increasing regimes of the front movement The study clearly identifies that bed movement is an important parameter for consideration in a co-current configuration towards establishing the effective bed movement. The study also highlights the importance of surface area to volume ratio of the particles in the packed bed and its influence on the volatile generation. Finally, the gas composition for air gasification under various air mass fluxes is compared with the experimental results. (C) 2016 Elsevier B.V. All rights reserved.

Modelling and analysis of an open-loop induction motor drive incorporating the effect of inverter dead-time

The objective of this paper is to study the influence of inverter dead-time on steady as well as dynamic operation of an open-loop induction motor drive fed from a voltage source inverter (VSI). Towards this goal, this paper presents a systematic derivation of a dynamic model for an inverter-fed induction motor, incorporating the effect of inverter dead-time, in the synchronously revolving dq reference frame. Simulation results based on this dynamic model bring out the impact of inverter dead-time on both the transient response and steady-state operation of the motor drive. For the purpose of steady-state analysis, the dynamic model of the motor drive is used to derive a steady-state model, which is found to be non-linear. The steady-state model shows that the impact of dead-time can be seen as an additional resistance in the stator circuit, whose value depends on the stator current. Towards precise evaluation of this dead-time equivalent resistance, an analytical expression is proposed for the same in terms of inverter dead-time, switching frequency, modulation index and load impedance. The notion of dead-time equivalent resistance is shown to simplify the solution of the non-linear steady-state model. The analytically evaluated steady-state solutions are validated through numerical simulations and experiments.

Increasing Critical Sensitivity of the Load/Unload Response Ratio before Large Earthquakes with Identified Stress Acclumulation Pattern

The Load/Unload Response Ratio (LURR) method is proposed for short-to-intermediate-term earthquake prediction [Yin, X.C., Chen, X.Z., Song, Z.P., Yin, C., 1995. A New Approach to Earthquake Prediction — The Load/Unload Response Ratio (LURR) Theory, Pure Appl. Geophys., 145, 701–715]. This method is based on measuring the ratio between Benioff strains released during the time periods of loading and unloading, corresponding to the Coulomb Failure Stress change induced by Earth tides on optimally oriented faults. According to the method, the LURR time series usually climb to an anomalously high peak prior to occurrence of a large earthquake. Previous studies have indicated that the size of critical seismogenic region selected for LURR measurements has great influence on the evaluation of LURR. In this study, we replace the circular region usually adopted in LURR practice with an area within which the tectonic stress change would mostly affect the Coulomb stress on a potential seismogenic fault of a future event. The Coulomb stress change before a hypothetical earthquake is calculated based on a simple back-slip dislocation model of the event. This new algorithm, by combining the LURR method with our choice of identified area with increased Coulomb stress, is devised to improve the sensitivity of LURR to measure criticality of stress accumulation before a large earthquake. Retrospective tests of this algorithm on four large earthquakes occurred in California over the last two decades show remarkable enhancement of the LURR precursory anomalies. For some strong events of lesser magnitudes occurred in the same neighborhoods and during the same time periods, significant anomalies are found if circular areas are used, and are not found if increased Coulomb stress areas are used for LURR data selection. The unique feature of this algorithm may provide stronger constraints on forecasts of the size and location of future large events.

Molecular dynamics simulation of hydrogen enhancing dislocation emission

The interactive pair potential between Al and H is obtained based on the ab initio calculation and the Chen-Mobius 3D lattice inversion formula. By utilizing the pair potentials calculated, the effects of hydrogen on the dislocation emission from crack tip have been studied. The simulated result shows that hydrogen can reduce the cohesive strength for Al single crystal, and then the critical stress intensity factor for partial dislocation emission decreases from 0.11 MPa root m (C-H = 0) to 0.075 MPa root m (C-H=0.72%) and 0.06 MPa root m (C-H = 1.44%). This indicates thar hydrogen can enhance the dislocation emission. The simulation also shows that atoms of hydrogen can gather and turn into small bubbles, resulting in enhancement of the equilibrium vacancy concentration.

The hemodynamic effects of in-tandem carotid artery stenosis: implications for carotid endarterectomy.

OBJECTIVES: It remains controversial whether patients with severe disease of the internal carotid artery and a coexisting stenotic lesion downstream would benefit from a carotid endarterectomy (CEA) of the proximal lesion. The aim of this study was to simulate the hemodynamic and wall shear effects of in-tandem internal carotid artery stenosis using a computational fluid dynamic (CFD) idealized model to give insight into the possible consequences of CEA on these lesions. METHODS: A CFD model of steady viscous flow in a rigid tube with two asymmetric stenoses was introduced to simulate blood flow in arteries with multiple constrictions. The effect of varying the distance between the two stenoses, and the severity of the upstream stenosis on the pressure and wall shear stress (WSS) distributions on the second plaque, was investigated. The influence of the relative positions of the two stenoses was also assessed. RESULTS: The distance between the plaques was found to have minimal influence on the overall hemodynamic effect except for the presence of a zone of low WSS (range -20 to 30 dyne/cm2) adjacent to both lesions when the two stenoses were sufficiently close (<4 times the arterial diameter). The upstream stenosis was protective if it was larger than the downstream stenosis. The relative positions of the stenoses were found to influence the WSS but not the pressure distribution. CONCLUSIONS: The geometry and positions of the lesions need to be considered when considering the hemodynamic effects of an in-tandem stenosis. Low WSS is thought to cause endothelial dysfunction and initiate atheroma formation. The fact that there was a flow recirculation zone with low WSS in between the two stenoses may demonstrate how two closely positioned plaques may merge into one larger lesion. Decision making for CEA may need to take into account the hemodynamic situation when an in-tandem stenosis is found. CFD may aid in the risk stratification of patients with this problem.

Evaluación de diferentes niveles de ofrecimiento de concentrado comercial adicionando forraje verde ad libitum en conejos durante el período de ceba

El ensayo estudió el efecto de cuatro niveles de ofrecimiento de concentrado comercial, adicionando forraje verde ad libitum en conejos durante el período de ceba. El forraje verde suministrado, consistió en una mezcla pi­cada, que contenía en base a peso fresco el 75% de hojas de musa. sp (plátano), 15% de hojas cajanus cajan (gandul) y 15% de hojas de pennisetum purpureum (taiwán). En el tratamiento utilizado como testigo T1, se suministró pienso comercial en cantidades en gramos por día por gazapo de 96, 129, 145, 158 y 162 para las semanas uno, dos, tres y cuatro respectivamente, para el tratamiento T2, se suministró el 75% del concentrado comercial ofrecido en T1, para el trata­ miento T3, se suministró el 50% del concentrado comercial ofre­cido en T1 y para el tratamiento T4, se suministró el 25% del concentrado comercial ofrecido en T1. Se utilizó un D C A (Diseño completamente aleatorio), incluyendo la covariable peso inicial. El período de evaluación fue de 35 días, con un tiempo de adaptación al alimento de 5 días. Las unidades experimentales fueron 22 gazapos al destete de 34 y 35 días de edad, nacidos en la granja, presentado caracteristicas entre las razas: Neozelandis, California, Pardo, Mariposa y Chinchilla. Se encontró efecto significativo al 0.05 para los tratamientos y no significativo al 0.05 para la covariable peso inicial, siendo las variables respuestas: Consumo de concentrado, consumo de forraje, ganancia media diaria, relación consumo de concentrado entre incremento de peso y relación consumo de forraje entre incremento de peso. Se obtuvieron ganancias medias promedios en gramos por día de 32.2, 28.57, 25.03 y 12.82. Los costos de alimentación en córdobas por gazapo en los 35 días de evaluación fueron 8.23, 6.29, 4.33 y 2.39, que se determinaron en base al análisis de presupuestos parciales, obteniendo un beneficio neto en córdobas de 32.95, 31.66, 30.28 y 21.619 para los tratamientos T1, T2, T3 y T4 respectivamente, a una taza de cambio de C$8.05: US$ 1.

Estudio preliminar de la utilización de la manteca de armadillo (Dasypus novemcinctus) en el tratamiento de la mastitis bovina en el municipio de Paiwas departamento de Región Autónoma del Atlántico Norte (RAAN)

El presente estudio se realizo con el objetivo de utilización de la manteca de Armadillo (Dasypus novemcinctus)en el tratamiento de la mastitis bovina en el Municipio de PAIWAS Departamento de Región Autónoma del Atlántico Norte (RAAN).Se localiza entre las coordenadas 12° 47' de latitud norte y 85° 07', con una altura sobre el nivel del mar de 145.88 msnm. una temperaturas entre 24°C y 25°C. La precipitación anual oscila entre los 2,400 mm y los 3,000 mm con una buena distribución durante todo el año. Se utilizo un diseño completamente al azar (D.C.A) el que esta compuesto por un lote de 30 animales divididas en 3 grupos, cada grupo formado por 10 animales seleccionadas al azar y sometidas a tratamientos distintos Tratamiento I: Mastivet complex, Tratamiento II: Manteca de cusuco al 100%. Tratamiento III: Manteca de cusuco al 50%. Existe una prevalencia de la mastitis en el hato del 65% de esto el 39% de mastitis subclínica y el 22.4% de mastitis clíni ca, y 74 vacas resultaron negativas a la prueba representando el 35.2%. EL cuarto mas afectado fue el Anterior derecho (AD) del cual el 48.5 % reaccionaron positivos. Los tratamiento III y II a base de manteca de del armadillo (Dasypus novemcinctus) tuvieron mejores resultados clínico-terapéuticos en la curación de la mastitis bovina, donde a los 42 días se alcanzó la mayor efectividad; ya que el tratamiento I la efectividad fue del 60 % ,en el II del 70 % y en el III del 80%. Los tratamientos alternativos (III y II) a base de manteca de del armadillo (Dasypus novemcinctus)mostraron factibilidad económica y terapéuticas.

Dynamic function of damage and its implications

Dynamic function of damage is the key to the problem of damage evolution of solids. In order to understand it, one must understand its mesoscopic mechanisms and macroscopic formulation. In terms of evolution equation of microdamage and damage moment, a dynamic function of damage is strictly defined. The mesoscopic mechanism underlying self-closed damage evolution law is investigated by means of double damage moments. Numerical results of damage evolution demonstrate some common features for various microdamage dynamics. Then, the dynamic function of damage is applied to inhomogeneous damage field. In this case, damage evolution rate is no longer equal to the dynamic function of damage. It is found that the criterion for damage localization is closely related to compound damage. Finally, an inversion of damage evolution to the dynamic function of damage is proposed.

Terapia homeopatica con Nosode en el control de mastitis bovina en Finca Santa Ana, municipio de Paiwas de la RAAS, Nicaragua

El presente trabajo se realizó en la finca Santa Ana Ana ubicada en las coordenadas de latitud Norte de 12º 47’longitud Oeste de 85º 07’y una altitud aproximada de 145.88 msnm en el Municipio de Paiwas, Departamento de la RAAS. Con el objetivo de evaluar un tratamiento homeopático (nosode de leche–mastitis-CH 7)contra mastitis bovina la cual es normalmente atendida por antibióticos, durante el trabajo de investigación se aplicaron tres tratamientos: I aplicación pliegue ano caudal, II aplicación sublingual y III tratamiento testigo con masticilina. Se seleccionaron 30 vacas con mastitis dividiéndolos en tres grupos de 10 cada uno donde las hembras se encontraban entre dos y tres meses de lactancia. Se encontró diferencia altamente significativa (P<0.01) para las variables fecha y vacas, y significativa (P<0.05), para las variables tratamiento y cuartos afectados. En los tratamientos el que controló mejor las afecciones en menos tiempo fue el químico, seguido del nosode de aplicación ano caudal, y el de menor control el nosode de aplicación sublingual, aunque este no difirió significativamente del nosode de aplicación ano caudal El cuarto que presentó la mayor afectación fue el cuarto trasero derecho (64%) seguido del cuarto delantero derecho (61%), el delantero izquierdo presentó la menor afectación con 49%, y el trasero izquierdo un porcentaje de afectación intermedia de 53%.

Influence of ion energy and substrate temperature on the optical and electronic properties of tetrahedral amorphous carbon (ta-C) films

The properties of amorphous carbon (a-C) deposited using a filtered cathodic vacuum arc as a function of the ion energy and substrate temperature are reported. The sp3 fraction was found to strongly depend on the ion energy, giving a highly sp3 bonded a-C denoted as tetrahedral amorphous carbon (ta-C) at ion energies around 100 eV. The optical band gap was found to follow similar trends to other diamondlike carbon films, varying almost linearly with sp2 fraction. The dependence of the electronic properties are discussed in terms of models of the electronic structure of a-C. The structure of ta-C was also strongly dependent on the deposition temperature, changing sharply to sp2 above a transition temperature, T1, of ≈200°C. Furthermore, T1 was found to decrease with increasing ion energy. Most film properties, such as compressive stress and plasmon energy, were correlated to the sp3 fraction. However, the optical and electrical properties were found to undergo a more gradual transition with the deposition temperature which we attribute to the medium range order of sp2 sites. We attribute the variation in film properties with the deposition temperature to diffusion of interstitials to the surface above T1 due to thermal activation, leading to the relaxation of density in context of a growth model. © 1997 American Institute of Physics.

Contabilidad y estados contables : implicancias del nuevo ordenamiento del Código Civil y Comercial de la Nación

Resumen: El presente artículo se corresponde con aspectos del nuevo ordenamiento contable establecido en el texto normativo del Código Civil y Comercial de la Nación – Ley 26.994- que entrará en vigencia el 1 de agosto de 2015. Profundizamos el análisis de la parte pertinente a CONTABILIDAD y ESTADOS CONTABLES. (Arts. 320 a 331 y artículos relacionados - Arts.145 a 148). Las novedades más relevantes se refieren a la clasificación de las personas en humanas y jurídicas (públicas y privadas); la definición de los sujetos obligados a llevar registro contable, los excluidos de hacerlo, los libros a emplear, el modo de llevarlos y ciertos requisitos. También incluye disposiciones sobre los Estados Contables y la documentación respaldatoria. Las reformas incluidas en el Código unificado aún no logran dar respuestas a los requerimientos de los profesionales en Ciencias Económicas, que desempeñan un rol protagónico en la aplicación de dichas normas.

An in vitro transposon system for highly regulated gene expression: construction of Escherichia coli strains with arabinose-dependent growth at low temperatures.

Placing a gene of interest under the control of an inducible promoter greatly aids the purification, localization and functional analysis of proteins but usually requires the sub-cloning of the gene of interest into an appropriate expression vector. Here, we describe an alternative approach employing in vitro transposition of Tn Omega P(BAD) to place the highly regulable, arabinose inducible P(BAD) promoter upstream of the gene to be expressed. The method is rapid, simple and facilitates the optimization of expression by producing constructs with variable distances between the P(BAD) promoter and the gene. To illustrate the use of this approach, we describe the construction of a strain of Escherichia coli in which growth at low temperatures on solid media is dependent on threshold levels of arabinose. Other uses of the transposable promoter are also discussed.

Some advances in study of crack identification problems

In the present paper, the crack identification problems are investigated. This kind of problems belong to the scope of inverse problems and are usually ill-posed on their solutions. The paper includes two parts: (1) Based on the dynamic BIEM and the optimization method and using the measured dynamic information on outer boundary, the identification of crack in a finite domain is investigated and a method for choosing the high sensitive frequency region is proposed successfully to improve the precision. (2) Based on 3-D static BIEM and hypersingular integral equation theory, the penny crack identification in a finite body is reduced to an optimization problem. The investigation gives us some initial understanding on the 3-D inverse problems.