Cleavage of poly(A)-binding protein by enterovirus proteases concurrent with inhibition of translation in vitro

Many enteroviruses, members of the family Picornaviridae, cause a rapid and drastic inhibition of host cell protein synthesis during infection, a process referred to as host cell shutoff. Poliovirus, one of the best-studied enteroviruses, causes marked inhibition of host cell translation while preferentially allowing translation of its own genomic mRNA. An abundance of experimental evidence has accumulated to indicate that cleavage of an essential translation initiation factor, eIF4G, during infection is responsible at least in part for this shutoff. However, evidence from inhibitors of viral replication suggests that an additional event is necessary for the complete translational shutoff observed during productive infection. This report examines the effect of poliovirus infection on a recently characterized 3' end translational stimulatory protein, poly(A)-binding protein (PABP). PABP is involved in stimulating translation initiation in lower eukaryotes by its interaction with the poly(A) tail on mRNAs and has been proposed to facilitate 5'-end-3'-end interactions in the context of the closed-loop translational model. Here, we show that PABP is specifically degraded during poliovirus infection and that it is cleaved in vitro by both poliovirus 2A and 3C proteases and coxsackievirus B3 2A protease. Further, PABP cleavage by 2A protease is accompanied by concurrent loss of translational activity in an in vitro-translation assay. Similar loss of translational activity also occurs simultaneously with partial 3C protease-mediated cleavage of PABP in translation assays. Further, PABP is not degraded during infections in the presence of guanidine-HCl, which blocks the complete development of host translation shutoff. These results provide preliminary evidence that cleavage of PABP may contribute to inhibition of host translation in infected HeLa cells, and they are consistent with the hypothesis that PABP plays a role in facilitating translation initiation in higher eukaryotes.     

Light flicker test in the United States

Home appliances, like washers, dryers, refrigerators, etc., can cause voltage fluctuations and light flicker. A standardized flicker test has been established in Europe (IEC 1000-3-3). However, the European test is designed for 230-V 50-Hz power and needs to be modified for a 115-V 60-Hz supply. In this paper, the reference impedance and the limits of flicker tests for 115 V/60 Hz systems are proposed. A high-performance power analysis system, the Xitron 2803AH power analyzer, was used to study the voltage fluctuations and flicker caused by some washing machines. The analysis and test results provided in this paper can serve as a proposal for establishing a US light flicker testing standard for 115 V/60 Hz     

Fast diffusers in a thermal gradient (solder ball)

The behaviour of Ni in Sn under a thermal gradient driving forces was calculated considering boundary conditions typical of lead-free solder applications. The steady state concentration profiles for a fast diffuser were determined and the consequences for reliability discussed.     

Probabilistic modelling, inference and learning using logical theories

This paper provides a study of probabilistic modelling, inference and learning in a logic-based setting. We show how probability densities, being functions, can be represented and reasoned with naturally and directly in higher-order logic, an expressive formalism not unlike the (informal) everyday language of mathematics. We give efficient inference algorithms and illustrate the general approach with a diverse collection of applications. Some learning issues are also considered.     

The precipitation of the Q phase in an AA6111 Alloy

The precipitation behavior of the quaternary Q phase in an Al 6111 alloy has been studied by analytical electron microscopy. The transformation strain associated with the Q phase has been determined from high resolution electron microscopy and electron diffraction. The habit plane of the Q laths is shown to be fully coherent with the Al matrix. The transformation strain is used to explain the pattern of heterogeneous precipitation of the Q phase at dislocations and grain boundaries. The crystal structure and composition of the Q phase, whether it forms in the matrix or at grain boundaries, appears similar to that formed directly from the melt in a quaternary Al-Cu-Mg-Si alloy.     

Uncertainty in biomass supply estimates: Lessons from a Yakama Nation case study

The increasing demand for bioenergy in the United States necessitates detailed case studies of cost and supply to assess its feasibility. We have developed supply curves based on six feedstocks in five counties surrounding the Yakama Nation in central Washington using spatially explicit estimates of supply and transportation cost. The supply curves were used to examine a base case supply for a bioenergy plant, to analyze the effects of land ownership, and examine the impacts of uncertainty in parameters used to determine cost and supply. The results show that existing industries produce the cheapest supply of feedstock as a byproduct of their operations, while supplies harvested specifically for bioenergy are considerably more expensive. Fragmented land ownerships lead to the necessity of cooperation between owners and highlight the importance of a strong anchor supply close to the plant. Lastly, uncertainty in supply and cost parameters leads to larger ranges in available biomass, leading to reluctant investment in large plants.     

Triggering steam explosions of single drops of a molten ferrosilicon alloy with a simple encapsulated mechanical impactor

We have developed a simple and inexpensive encapsulated mechanical impactor that can be operated under water. The unit reproducibly generates upward-directed pressure transients in the water with peaks of approximately 0.13 MPa measured 100 mm above its surface. These pulses have been used to trigger steam explosions of drops of a molten ferrosilicon alloy when they are either just above the unit in free fall through the water or shortly after they land on its surface. The impactor is study, reliable, safe, and environmentally neutral and resets for reuse within seconds. Compared to other triggering techniques, the impactor does not generate light, bubbles, or strong water motion that obscure or appreciably affect the initiation or early stages of the steam explosions. This permits good imaging and measurements at essentially all times during the triggering and subsequent development of the explosions.     

The Management of Knowledge during Design and Implementation of Process Technologies

Knowledge and learning play a major part in the successful implementation of process technologies. We suggest that managers of implementation projects can improve the initial performance levels of the process in which a new technology resides by ensuring that useful knowledge, present in the organization at the start of the implementation project, is employed to greatest effect during the design of the modified process and that new learning is not lost. This does not necessarily require major investment in computerized systems – merely exploring what potentially useful knowledge is already available within the organization, or can readily be obtained from external contact, may improve the efficiency of technology implementation. Use of available knowledge can also help to speed up the implementation process by reducing the number of, and time required for, the adaptations necessary to get the process to the desired performance level.     

Forecasting reliability growth

This paper describes a method for estimating and forecasting reliability from attribute data, using the binomial model, when reliability requirements are very high and test data are limited. Integer data—specifically, numbers of failures — are converted into non-integer data. The rationale is that when engineering corrective action for a failure is implemented, the probability of recurrence of that failure is reduced; therefore, such failures should not be carried as full failures in subsequent reliability estimates. The reduced failure value for each failure mode is the upper limit on the probability of failure based on the number of successes after engineering corrective action has been implemented. Each failure value is less than one and diminishes as test programme successes continue. These numbers replace the integral numbers (of failures) in the binomial estimate. This method of reliability estimation was applied to attribute data from the life history of a previously tested system, and a reliability growth equation was fitted. It was then ‘calibrated’ for a current similar system's ultimate reliability requirements to provide a model for reliability growth over its entire life-cycle. By comparing current estimates of reliability with the expected value computed from the model, the forecast was obtained by extrapolation.     

A conceptual framework for examining adolescent identity, media influence, and social development.

The adolescent identity, media, and sociocognitive schema (AIMSS) framework offers a theoretical understanding of adolescent consumption and cognitive processing of media entertainment. Review and integration of mass communication theory, developmental theory, and ecological theory serves as the conceptual foundation. The framework outlines linkages between media exposure and adolescent development, in particular adolescent identity formation and social competence. A key contribution of the model is consideration of the positive and negative aspects of adolescent cognition and behavioral functioning. The present article offers several recommendations for testing the utility of the AIMSS framework. (PsycINFO Database Record (c) 2010 APA, all rights reserved)