Assessment of digital image correlation measurement errors: methodology and results

Optical full-field measurement methods such as Digital Image Correlation (DIC) are increasingly used in the field of experimental mechanics, but they still suffer from a lack of information about their metrological performances. To assess the performance of DIC techniques and give some practical rules for users, a collaborative work has been carried out by the Workgroup “Metrology” of the French CNRS research network 2519 “MCIMS (Mesures de Champs et Identification en Mécanique des Solides / Full-field measurement and identification in solid mechanics, http://www.ifma.fr/lami/gdr2519)”. A methodology is proposed to assess the metrological performances of the image processing algorithms that constitute their main component, the knowledge of which being required for a global assessment of the whole measurement system. The study is based on displacement error assessment from synthetic speckle images. Series of synthetic reference and deformed images with random patterns have been generated, assuming a sinusoidal displacement field with various frequencies and amplitudes. Displacements are evaluated by several DIC packages based on various formulations and used in the French community. Evaluated displacements are compared with the exact imposed values and errors are statistically analyzed. Results show general trends rather independent of the implementations but strongly correlated with the assumptions of the underlying algorithms. Various error regimes are identified, for which the dependence of the uncertainty with the parameters of the algorithms, such as subset size, gray level interpolation or shape functions, is discussed

Abscess of adrenal gland caused by disseminated subacute Nocardia farcinica pneumonia. A case report and mini-review of the literature

<p>Abstract</p> <p>Background</p> <p>Infections caused by <it>Nocardia farcinica </it>are uncommon and show a great variety of clinical manifestations in immunocompetent and immunocompromised patients. Because of its unspecific symptoms and tendency to disseminate it may mimic the clinical symptoms and radiologic findings of a tumour disease and the diagnosis of nocardiosis can easily be missed, because there are no characteristic symptoms.</p> <p>Case presentation</p> <p>We present a case of an adrenal gland abscess caused by subacute disseminated <it>N. farcinica </it>pneumonia.</p> <p>Conclusion</p> <p>An infection with <it>N. farcinica </it>is potentially lethal because of its tendency to disseminate -particularly in the brain- and its high resistance to antibiotics. Awareness of this differential diagnosis allows early and appropriate treatment to be administered.</p

Genome-wide DNA methylation map of human neutrophils reveals widespread inter-individual epigenetic variation

The extent of variation in DNA methylation patterns in healthy individuals is not yet well documented. Identification of inter-individual epigenetic variation is important for understanding phenotypic variation and disease susceptibility. Using neutrophils from a cohort of healthy individuals, we generated base-resolution DNA methylation maps to document inter-individual epigenetic variation. We identified 12851 autosomal inter-individual variably methylated fragments (iVMFs). Gene promoters were the least variable, whereas gene body and upstream regions showed higher variation in DNA methylation. The iVMFs were relatively enriched in repetitive elements compared to non-iVMFs, and were associated with genome regulation and chromatin function elements. Further, variably methylated genes were disproportionately associated with regulation of transcription, responsive function and signal transduction pathways. Transcriptome analysis indicates that iVMF methylation at differentially expressed exons has a positive correlation and local effect on the inclusion of that exon in the mRNA transcript

E2f1–3 switch from activators in progenitor cells to repressors in differentiating cells

In the established model of mammalian cell cycle control, the retinoblastoma protein (Rb) functions to restrict cells from entering S phase by binding and sequestering E2f activators (E2f1, E2f2 and E2f3), which are invariably portrayed as the ultimate effectors of a transcriptional program that commit cells to enter and progress through S phase(1,2). Using a panel of tissue-specific cre-transgenic mice and conditional E2f alleles we examined the effects of E2f1, E2f2 and E2f3 triple deficiency in murine embryonic stem cells, embryos and small intestines. We show that in normal dividing progenitor cells E2f1-3 function as transcriptional activators, but contrary to the current view, are dispensable for cell division and instead are necessary for cell survival. In differentiating cells E2f1-3 function in a complex with Rb as repressors to silence E2f targets and facilitate exit from the cell cycle. The inactivation of Rb in differentiating cells resulted in a switch of E2f1-3 from repressors to activators, leading to the superactivation of E2f responsive targets and ectopic cell divisions. Loss of E2f1-3 completely suppressed these phenotypes caused by Rb deficiency. This work contextualizes the activator versus repressor functions of E2f1-3 in vivo, revealing distinct roles in dividing versus differentiating cells and in normal versus cancer-like cell cycles