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The bimetallic oxides of general M4M'2O9 formula, where M=Fe, Co, Mn and M'=Nb or Ta, form a family of linear magnetoelectric materials, for which properties depend on the nature of the M,M' pair. In the present study, the structural, magnetic and magnetoelectric properties of a new member, Co2Fe2Ta2O9, synthesized in polycrystalline form, are reported. This compound crystallizing in the P‐3c1 trigonal '429' structure (a=5.2009 (1) Å, c=14.1986(1) Å and V=332.613(2) Å3) is found to be antiferromagnetic below TN=53 K. Although the structural features are intermediate between the Co4Ta2O9 and Fe4Ta2O9 limit members, a very different magnetoelectric behaviour is observed. In order to reveal the differences between M4M'2O9 with M=Fe or Co or mixed and M'=Ta or Nb, a comparison between these six compounds is proposed. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coil (STEC) causes a spectrum of human illnesses such as haemorrhagic colitis and haemolytic--uraemic syndrome. Although the locus of enterocyte effacement (LEE) seems to confer enhanced virulence, LEE-negative STEC strains are also associated with severe human disease, suggesting that other unknown factors enhance the virulence potential of STEC strains. A novel hybrid pathogenicity island, termed PAI [I.sub.CL3], has been previously characterized in the LEE-negative O113:H21 STEC strain CL3. Screening for the presence of PAI [I.sub.CL3] elements in 469 strains of E. coil, including attaching and effacing (A/E) pathogens [enteropathogenic E. coil (EPEC) and enterohaemorrhagic E. coil (EHEC)], non-A/E pathogens [LEE-negative STEC, extra-intestinal pathogenic E. coil (ExPEC), enterotoxigenic E. coil (ETEC) and enteroaggregative E. coil (EAEC)] and commensal E. coil isolates, showed that PAI [I.sub.CL3] is unique to LEE-negative STEC strains linked to disease, providing a new marker for these strains. We also showed that a PAI [I.sub.CL3]-equivalent gene cluster is present in the genome of Citrobacter rodentium, on a 53 kb genomic island inserted into the pheV tRNA locus. While the C. rodentium PAl [I.sub.CL3] shows high similarities at the nucleotide level and in organization with the E. coil PAI [I.sub.CL3], the genetic context of the integration differs completely. In addition, BLAST searches revealed that other E. coil pathotypes (O157:H7 EHEC, ExPEC, EPEC and EAEC) possess incomplete PAI [I.sub.CL3] elements that contain only the genes located at the extremities of the island. Six of the 16 sequenced E. coil genomes showed deleted PAI [I.sub.CL3] gene clusters which are carried on mobile genetic elements inserted into pheV, selC or serW tRNA loci, which is compatible with the idea that the PAI [I.sub.CL3] gene cluster entered E. coil and C. rodentium at multiple times through independent events. The phylogenetic distribution of the PAI [I.sub.CL3] variants suggests that a B1 genetic background is necessary for the maintenance of the full complement of PAI [I.sub.CL3] genes in E. coil.

Only a subset of Shiga toxin (Stx)-producing Escherichia coil (STEC) are human pathogens, but the characteristics that account for differences in pathogenicity are not well understood. In this study, we investigated the distribution of the stx variants coding for [Stx.sub.2] and its variants in highly virulent STEC of seropathotype A and low-pathogenic STEC of seropathotype C. We analysed and compared transcription of the corresponding genes, production of Shiga toxins, and stx-phage release in basal as well as in induced conditions. We found that the [stx.sub.2] variant was mainly associated with strains of seropathotype A, whereas most of the strains of seropathotype C possessed the [stX.sub.2_vhb] variant, which was frequently associated with [stx.sub.2], [stx.sub.2_vha] or [stx.sub.2c]. Levels of [stx.sub.2] and [stx.sub.2]-related mRNA were higher in strains belonging to seropathotype A and in those strains of seropathotype C that express the [stx.sub.2] variant than in the remaining strains of seropathotype C. The [stx.sub.2]-vhb genes were the least expressed, in basal as well as in induced conditions, and in many cases did not seem to be carried by an inducible prophage. A clear correlation was observed between stx mRNA levels and stx-phage DNA in the culture supernatants, suggesting that most [stx.sub.2]-related genes are expressed only when they are carried by a phage. In conclusion, some relationship between [stx.sub.2]-related gene expression in vitro and the seropathotype of the STEC strains was observed. A higher expression of the [stx.sub.2] gene and a higher release of its product, in basal as well as in induced conditions, was observed in pathogenic strains of seropathotype A. A subset of strains of seropathotype C shows the same characteristics and could be a high risk to human health.

The gastrointestinal tract (GIT) of ruminants is the main reservoir of enterohemorrhagic Escherichia coli, which is responsible for food-borne infections in humans leading to severe kidney disease. Characterization of biotic and abiotic factors that influence the carriage of these pathogens by the ruminant would help in the development of ecological strategies to reduce their survival in the GIT and to decrease the risk of contamination of animal products.

The influence of the Joule effect on the nonlinear behavior of the transport I-V curves in polycrystalline samples of the manganite Pr0.8Ca0.2MnO3 is evaluated by using the crystalline unit-cell parameters ass an internal thermometer in x-ray and neutron diffractions. The experiments show that the internal temperature gradient or the difference between the temperature of the sample and that of the thermal bath is at the origin of the nonlinearity observed in the I-V curves.

The foo operon encodes [F165.sub.1] fimbriae that belong to the P-regulatory family and are synthesized by septicemic Escherichia coli. Using an Lrp-deficient host and the lrp gene cloned under the arabinose pBAD promoter, we demonstrated that foo was transcribed proportionally to the amount of Lrp synthesized. L-Leucine and L-alanine decreased drastically the steady-state transcription of foo and modified phase variation, independently of the presence of Fool. Specific mutations in the C-terminal region of Lrp reduced or abolished the repressive effect of these amino acids, indicating that they modulate [F165.sub.1] by affecting Lrp.

Purpose. The final product of the Accreditation Council for Graduate Medical Education (ACGME) Outcomes Project is to improve health care through ensuring the competence of physicians during their training and beyond. Its success depends on a paradigm shift to a competency-based model of medical education. This article presents an overview of the model and describes the first stages of this multistep transition in a university setting. Our hope is to raise awareness of the impact on the pediatric community at large and provide a foundation on which other educators can continue to build. Methods. The ACGME established 6 domains of competence as the first step in the paradigm shift. To begin work on the second step of establishing benchmarks for evaluation of competence and thresholds at which they should be achieved, the educational leadership from the primary care departments formed a work group with the support of a Health Resources and Services Administration grant. Results. Review of the literature led us to embark on a stepwise process for initiating a competency-based system of medical education. We established the benchmarks by a process of individual effort followed by group consensus. These benchmarks, in the aggregate, permit an evaluator to determine whether a given competency has been achieved. The next phases of step 2 required setting thresholds for the demonstration of competence and finally establishing consensus regarding the threshold for competence at each level of training for each specific benchmark. To accomplish the latter, we surveyed the program directors of the 202 accredited pediatric training programs that are members of the Association of Pediatric Program Directors. Eighty-one members (40%) completed our survey. Although some controversy existed for thresholds during the postgraduate-year-1 level, majority consensus was reached for nearly all benchmarks at the upper levels of training. Impact of the shift to competencies for medical students and practicing physicians is also reviewed. Conclusion. Having defined the benchmarks and thresholds for the 6 ACGME domains of competence, we are well positioned to move to step 3: developing the necessary tools to evaluate competence. The move to competency-based education impacts the entire pediatric community. Lessons learned from our experience may be generalized and thus be of value to the community at large. Pediatrics 2004;113:252-258; competency-based education, medical education, residency training, maintenance of certification., The Accreditation Council for Graduate Medical Education (ACGME) has partnered with the American Board of Medical Specialties (ABMS) in responding to public concerns regarding accountability in health care and medical [...]

Objective. Studies of long-term outcome on nonaccidental head injury (NAHI) in young children have shown severe neurodevelopmental sequelae in most cases. For improving the knowledge of outcome and for identifying prognostic factors, additional clinical and cerebral imaging data are needed. The aim of this study was to describe clinical and imaging features over time and to consider their value for predicting neurodevelopmental outcome. Methods. A retrospective medical record review was conducted of 23 children with confirmed NAHI, for whom an extended follow-up of 2.5 to 13 years (mean: 6 years) was contemplated. Glasgow Coma Scale scores, severity of retinal hemorrhages, presence of skull fractures, cranial growth deceleration, and sequential neuroimaging data (computed tomography and/or magnetic resonance imaging) were compared with patterns of clinical evolution assessed by the Glasgow Outcome Scale. Results. Clinical outcome showed that 14 (61%) children had severe disabilities, 8 (35%) had moderate disabilities, and 1 (4%) was normal. A low initial Glasgow Coma Scale score, severe retinal hemorrhages, presence of skull fracture, and cranial growth deceleration were significantly associated with poor developmental outcome. Eighteen of the 23 patients had abnormal magnetic resonance imaging scans. This examination disclosed atrophy when performed beyond 15 days of injury. Atrophy seemingly resulted from various brain lesions, namely, contusions, infarcts, and other lesions within the white matter. Presence of intraparenchymal brain lesions within the first 3 months was significantly associated with neurodevelopmental impairment. Severity of motor and cognitive dysfunctions was related to the extent of intraparenchymal lesions. Conclusions. Early clinical and radiologic findings in NAHI are of prognostic value for neurodevelopmental outcome. Pediatrics 2003;112:808-814; nonaccidental head injury, traumatic brain injury, child abuse, shaken-infant syndrome, neuroimaging, outcome., ABBREVIATIONS. NAHI, nonaccidental head injury; SBS, shaken-baby syndrome; CT, computed tomography; MRI, magnetic resonance imaging; GCS, Glasgow Coma Scale; GOS, Glasgow Outcome Scale; GR, good recovery; MD, moderate disability; SD, [...]

Stx(sub 2)-restriction fragment length polymorphism, stx(sub 2) variant, and plasmid profile analysis is as accurate as pulsed-field gel electrophoresis for differentiating Shiga-toxin-producing strains of E. coli. In central France, many of the strains isolated from food, animals, and humans with hemolytic-uremic syndrome belonged to the O91 and OX3 serogroups.