The BAX PCR assay for screening Listeria monocytogenes targets a partial putative gene lmo2234

The BAX PCR for screening Listeria monocytogenes is a commercial PCR assay for specifically targeting L. monocytogenes, a foodborne pathogen that can contaminate a variety of foods and cause a potentially fatal disease, listeriosis, among high-risk populations. The high specificity (> 98%) of this PCR assay is achieved by targeting a species-specific genomic region (approximately 400 bp) presumably found only in L. monocytogenes. In this study, the identity of the BAX PCR-targeted genomic region was determined by using PCR cloning, DNA sequencing, and basic local alignment search tool (BLAST) analysis of the amplicon sequences of an L. monocytogenes serotype 1/2a strain. BLAST analysis identified the BAX PCR amplicon (GenBank accession no. AY364605) as a 423-bp genomic region between nucleotides 224,409 and 224,831 in the genome of L. monocytogenes (serotype 1/2a strain EGD-e), including a 145-bp noncoding region and a 278-bp partial coding sequence of a putative gene, lmo2234. The translated amino acid sequence (92 amino acids) of this partial coding region is highly conserved between L. monocytogenes and Listeria innocua (93% homology). Reverse-position-specific BLAST analysis identified a conserved domain in Lmo2234 that was similar (95.3% aligned, E value = 9E-18) to the consensus amino acid sequence of sugar phosphate isomerases/epimerases (National Center for Biotechnology Information conserved domain database accession no. COG 1082.1, IolE), indicating that Lmo2234 might be involved in bacterial carbohydrate transport and metabolism.     

A novel method for chip formation analyses in deep hole drilling with small diameters

Recent trends of downsizing and miniaturization of components, e.g. in the automotive industry for the manufacturing of fuel injectors or in the medical industry for the production of bone screws or surgical instruments, increase the importance of mechanical deep hole drilling with small diameters. Unfortunately, there are still some open challenges regarding this process. In addition to the unfavorable ratio of the cutting edge rounding to the achievable feed rates and undeformed chip thicknesses which results in significant mechanical tool loads, the control of the chip formation and the removal constitutes a major difficulty. The slender tool dimensions, especially the small cross sections of the chip flutes, necessitate a favorable chip formation to achieve the required process safety and productivity. Therefore, analyses of the chip formation, when machining difficult-to-cut materials provide the means for an effective process design. This analysis, however, is particularly difficult due to the closed operating zone. Quick-stop devices used for the chip formation analyses so far are limited in the tool diameter respectively the revolution speed. Furthermore the informative value is limited, because a quick-stop test takes a significant time to stop and thus the instantaneous cutting conditions during the tool retraction are altered. To overcome these restrictions, a new method for the analysis of the chip formation in small diameter deep hole drilling is presented in this paper. It is based on the utilization of a high-speed camera and tailored material samples. The experimental set-up and the results of first analyses conducted under minimum quantity lubrication are presented. The chip formation process is analyzed for the single-lip gun drilling of the nickel-based alloy Inconel718 and the bainitic steel 20MnCrMo7.     

Spent nuclear fuel and residential property values: the influence of proximity, visual cues and public information

This article examines whether public knowledge of spent fuel storage at nuclear power plants, and any local adverse risk perceptions that may have occurred, affect the sale price of single-family residential properties. We present evidence from the Rancho Seco, California, plant on residential property values using an hedonic modeling framework. We include a large number of control variables, data with a high level of spatial detail and a number of public information variables in order to model property market effects within a fifteen mile radius of the plant. Our findings indicate that proximity and visual reminders of the plant have some influence on local property markets, and that there is a small media coverage effect on single-family home sale prices. Received: 6 May 1998 / Accepted: 26 May 1999     

Characterization of Impact Damage in Ultra-High Performance Concrete Using Spatially Correlated Nanoindentation/SEM/EDX

Little work has been done to study the fundamental material behaviors and failure mechanisms of cement-based materials including ordinary Portland cement concrete and ultra-high performance concretes (UHPCs) under high strain impact and penetration loads at lower length scales. These high strain rate loadings have many possible effects on UHPCs at the microscale and nanoscale, including alterations in the hydration state and bonding present in phases such as calcium silicate hydrate, in addition to fracture and debonding. In this work, the possible chemical and physical changes in UHPCs subjected to high strain rate impact and penetration loads were investigated using a novel technique wherein nanoindentation measurements were spatially correlated with images using scanning electron microscopy and chemical composition using energy dispersive x-ray microanalysis. Results indicate that impact degrades both the elastic modulus and indentation hardness of UHPCs, and in particular hydrated phases, with damage likely occurring due to microfracturing and debonding.     

Preliminary core set of domains and reporting requirements for longitudinal observational studies in rheumatology

The minimized energy mapping of annexin V Trp-187 chi1 x chi2 isomerization supports the existence of two preferential rotameric orientations of the Trp side chain upon annexin V binding to membranes, in agreement with the time-resolved fluorescence results. They correspond to the perpendicular trans (-173 degrees, 73 degrees) and g- (-71 degrees, 83 degrees) rotamers and represent 59 and 28% of the population, respectively. The analysis of their local environment makes it possible to assign the trans rotamer to the long component and the g- rotamer to the short component of the biexponential fluorescence decay. The orientation of these rotamers relative to the protein core suggests a dual role for Trp-187, which might be involved both in the interaction with the phospholipid bilayer and in the formation of the annexin V 2-D array at the surface of the membrane.