Escherichia coli O157:H7 is the largest cause of hemolytic uremic syndrome (HUS). Previous studies proposed that HUS risk varies across the E. coli O157:H7 phylogenetic tree (hypervirulent clade 8), but the role of age in the association is unknown. We determined phylogenetic lineage of E. coli O157:H7 isolates from 1160 culture-confirmed E. coli O157:H7 cases reported in Washington State, 2004–2015. Using generalised estimating equations, we tested the association between phylogenetic lineage and HUS. Age was evaluated as an effect modifier. Among 1082 E. coli O157:H7 cases with both phylogenetic lineage and HUS status (HUS n = 76), stratified analysis suggested effect modification by age. Lineages IIa and IIb, relative to Ib, did not appear associated with HUS in children 0–9-years-old. For cases 10–59-years-old, lineages IIa and IIb appeared to confer increased risk of HUS, relative to lineage Ib. The association reversed in ⩾60-year-olds. Results were similar for clade 8. Phylogenetic lineage appears to be associated with HUS risk only among those ⩾10-years-old. Among children <10, the age group most frequently affected, lineage does not explain progression to HUS. However, lineage frequency varied across age groups, suggesting differences in exposure and/or early disease manifestation.

We describe the investigation of two temporally coincident illness clusters involving salmonella and Staphylococcus aureus in two states. Cases were defined as gastrointestinal illness following two meal events. Investigators interviewed ill persons. Stool, food and environmental samples underwent pathogen testing. Alabama: Eighty cases were identified. Median time from meal to illness was 5·8 h. Salmonella Heidelberg was identified from 27 of 28 stool specimens tested, and coagulase-positive S. aureus was isolated from three of 16 ill persons. Environmental investigation indicated that food handling deficiencies occurred. Colorado: Seven cases were identified. Median time from meal to illness was 4·5 h. Five persons were hospitalised, four of whom were admitted to the intensive care unit. Salmonella Heidelberg was identified in six of seven stool specimens and coagulase-positive S. aureus in three of six tested. No single food item was implicated in either outbreak. These two outbreaks were linked to infection with Salmonella Heidelberg, but additional factors, such as dual aetiology that included S. aureus or the dose of salmonella ingested may have contributed to the short incubation periods and high illness severity. The outbreaks underscore the importance of measures to prevent foodborne illness through appropriate washing, handling, preparation and storage of food.

We have previously reported, based on fluctuation electron microscopy (FEM) data, that Zr50Cu45Al5 bulk metallic glass (BMG) contains significant icosahedral and crystal-like medium-range order. Here, we report similar finding for Zr54Cu38Al8 BMG, which is a poorer glass former. Like Zr50Cu45Al5, Zr54Cu38Al8 contains icosahedral and crystal-like structures. In the as-cast state, the crystal-like peak in the FEM data is stronger than icosahedral-like peak. After annealing at 0.83Tg (573 K), the icosahedral-like peak increases, but, unlike Zr50Cu45Al5, the crystal-like peak does not decrease. This tendency toward stronger, more thermally stable crystal-like order may be associated with the poorer glass forming ability of Zr54Cu38Al8.

Twelve manic patients were treated for 2 weeks with oral haloperidol; in 6 patients treatment commenced with intravenous haloperidol, and intravenous ‘test’ doses were given after 1, 3–5 and 14 days of oral medication. From 24 hours to 14 days baseline serum prolactin levels rose towards a plateau, as did the improvement in clinical ratings. After the first intravenous test doses of haloperidol, prolactin levels peaked at 1 hour; however, they fell to a low point at 24 hours, and no response to further test doses was seen for 3–5 days. The response tended to return at 14 days. The mechanisms underlying the changes in prolactin levels, and in clinical state, are discussed.

Escherichia coli O157.H7 was found in 10 of 3570 (0·28%) faecal samples from dairy cattle in 5 of 60 herds (8·3%). Several tentative associations with manure handling and feeding management practices on dairy farms were identified. Faecal/urine slurry samples, bulk milk samples, and milk filters from dairy herds were negative for E. coli 0157.H7. E. coli 0157.H7 was also isolated from 10 of 1412 (0·71 %) faecal samples from pastured beef cattle in 4 of 25 (16%) herds. The prevalence of E. coli 0157. H7 excretion in feedlot beef cattle was 2 of 600 (0·33 %). The identification of cattle management practices associated with colonization of cattle by E. coli 0157.H7 suggests the possibility that human E. coli O157.H7 exposure may be reduced by cattle management procedures.

Cu47Ti34Zr11Ni8 amorphous gas atomized powders were consolidated by warm extrusion. After consolidation near 723 K using an extrusion ratio of 5, the material retains between 88% and 98% of the amorphous structure found in the gas atomized powder. The onsets of the glass transition and crystallization temperatures of this extruded material are observed respectively at slightly higher and lower temperatures than those of the starting powders. These temperature shifts are attributed to a composition change in the remaining amorphous phase during partial devitrification throughout the extrusion process. Powders extruded at the same temperature, but using higher extrusion ratios of 9 and 13, exhibit substantial devitrification during the consolidation process yet still deform homogeneously.

CoSi2 has emerged as the silicide of choice for 0.18μm CMOS technologies and below. Robustness and scaling-performance of an integrated CoSi2-module, however, is shown to critically depend upon careful optimization of each individual process-step. The impact of surface-preparation, capping layer, initial Co-thickness and thermal processing will be discussed. The scalability of an optimized process meeting all major requirements for application to ULSI devices is demonstrated for gate-length down to 60nm.

Laboratory-based surveillance of salmonella isolates serotyped at four state health departments (Illinois, Michigan, Minnesota and Wisconsin) led to the identification of multistate outbreaks of salmonella infections during 1990 (176 cases of S. javiana) and 1993 (100 cases of S. montevideo). Community-based case-control studies and product traceback implicated consumption of tomatoes from a single South Carolina tomato packer (Packer A) MOR 16·0; 95% CI 2·1, 120·6; P<0·0001 in 1990 and again in 1993 (MOR 5·7; 95% CI 1·5, 21·9; P=0·01) as the likely vehicle. Contamination likely occurred at the packing shed, where field grown tomatoes were dumped into a common water bath. These outbreaks represent part of a growing trend of large geographically dispersed outbreaks caused by sporadic or low-level contamination of widely distributed food items. Controlling contamination of agricultural commodities that are also ready-to-eat foods, particularly fruits and vegetables, presents a major challenge to industry, regulators and public health officials.

The introduction of rapid thermal processing for silicide formation has triggered a lot of research to temperature uniformity and reproducibility in RTP systems. In addition to the temperature, the ambient control is to be taken into account. Although gasses are specified to a low level of contaminants, the RTP step needs to be optimised for optimal contaminant reduction. Besides, the process wafer itself is a source of contamination.

In this paper an overview will be given of the role of RTP ambient on the silicidation processes. The effect of the wafer on ambient purity will be highlighted. It will be shown that the use of a reactive capping layer during silicidation represents an adequate solution for both sources of contamination.

The effect of capping layer (Ti vs TiN) on CoSi formation and CoSi2 sheet resistance has been investigated. Resistance measurements and XTEM analysis have been used to show that the Ti cap lowers the activation energy for CoSi formation by gettering the O2 from the RTA (rapid thermal anneal) ambient and eliminating the formation of SiO2 between the growing CoSi and the Co. The sheet resistance of cobalt silicide formed from Co/Ti and Co/TiN bilayers on poly- Si lines was measured as a function of linewidth and RTA temperature. With a Ti cap, the sheet resistance is low and independent of temperature, and the RTA process window is large.

Escherichia coli O157 shedding in 14 cattle herds was determined by faecal culture at intervals of approximately 1 month for up to 13 months. The overall prevalence was 1·0% (113/10832 faecal samples) and 9 of the 14 herds were detected as positive. Herds positive 2 years previously (n=5) had a higher prevalence of positive cattle (median=1·9%) than herds which had been negative on a previous sampling (n=8, median=0·2%). Weaned heifers had a higher prevalence (1·8%) than did unweaned calves (0·9%) or adults (0·4%). For all herds the highest prevalence occurred in the summer months, which resulted in most of the positive faecal samples being collected on a minority of sampling visits.

Novel metal deposition stack and damascene processing methods have been used to fabricate electrically isolated parallel arrays of 1.0 μm deep aluminum-alloy interconnect trenches varying in width from 0.5 μm to 16 μm. The grain size and crystallographic texture of the Al in these trenches has been characterized using transmission electron microscopy (TEM) and local electron backscattered diffraction (EBSD), respectively. Narrow lines (0.5 and 1.0 μm wide) have a bamboo microstructure, intermediate widths (2.0 μm wide) are nearly bamboo, and wide lines (4.0 μ and wider) are polycrystalline. The <111> texture of the lines degrades with decreasing linewidth. A secondary <100> component is demonstrated and its origin proposed. The electromigration reliability of the narrow damascene Al lines was measured, and the observed enhancement of damascene Al interconnects compared to conventionally-fabricated Al interconnects is correlated with the microstructure.

Novel metal deposition stack and damascene processing methods have been used to fabricate electrically isolated parallel arrays of 1.0 νm deep aluminum-alloy interconnect trenches varying in width from 0.5 μm to 16 μm. The grain size and crystallographic texture of the Al in these trenches has been characterized using transmission electron microscopy (TEM) and local electron backscattered diffraction (EBSD), respectively. Narrow lines (0.5 and 1.0 μm wide) have a bamboo microstructure, intermediate widths (2.0 μm wide) are nearly bamboo, and wide lines (4.0 μm and wider) are polycrystalline. The <111> texture of the lines degrades with decreasing linewidth. A secondary <100> component is demonstrated and its origin proposed. The electromigration reliability of the narrow damascene Al lines was measured, and the observed enhancement of damascene Al interconnects compared to conventionally-fabricated Al interconnects is correlated with the microstructure.

In narrow metal lines used for chip level interconnects, the line width can strongly affect the electromigration reliability, typically due to variations in the microstructure and in the mechanical stress state. These variations have a stronger effect as the line width decreases to the order of the metal grain size or less. Electromigration failure distributions were obtained both experimentally and by simulation for realistic interconnect structures with six different line widths, ranging from lμm to 8μm. In order to simulate the electromigration failure distributions, microstructure statistics were obtained (using TEM) and the critical void volume for failure was measured (using SEM) for each line width. The simulated failure times match the experimental failure times for narrow line widths (1-4μm).

The electromigration failure mode and failure rate during accelerated electromigration testing is expected to be strongly affected by the mechanical stress state of Al lines, since tensile stress and compressive stress states favor void growth and hillock formations (extrusions), respectively. During electromigration testing, the mechanical stress state or evolution of mechanical stress of an interconnect is a function of current density and temperature, the two principal variables in electromigration testing. In our experiments, we have observed two different electromigration failure modes by varying the current density and temperatures where (i) the passivated Al lines tested at high current density and high temperatures failed by extrusion or hillock type failure and (ii) the interconnect lines tested at low current density and moderate temperature failed by voiding. A mechanical stress model which incorporates both the thermally generated stress and electromigration induced mechanical stress is invoked to explain the electromigration failure mode selection observed in our experiments.