Review of quantitative phase-digital holographic microscopy: promising novel imaging technique to resolve neuronal network activity and identify cellular biomarkers of psychiatric disorders.

Quantitative phase microscopy (QPM) has recently emerged as a new powerful quantitative imaging technique well suited to noninvasively explore a transparent specimen with a nanometric axial sensitivity. In this review, we expose the recent developments of quantitative phase-digital holographic microscopy (QP-DHM). Quantitative phase-digital holographic microscopy (QP-DHM) represents an important and efficient quantitative phase method to explore cell structure and dynamics. In a second part, the most relevant QPM applications in the field of cell biology are summarized. A particular emphasis is placed on the original biological information, which can be derived from the quantitative phase signal. In a third part, recent applications obtained, with QP-DHM in the field of cellular neuroscience, namely the possibility to optically resolve neuronal network activity and spine dynamics, are presented. Furthermore, potential applications of QPM related to psychiatry through the identification of new and original cell biomarkers that, when combined with a range of other biomarkers, could significantly contribute to the determination of high risk developmental trajectories for psychiatric disorders, are discussed.

Coronary vasomotor responses to isometric handgrip exercise are primarily mediated by nitric oxide: a noninvasive MRI test of coronary endothelial function.

Endothelial cell release of nitric oxide (NO) is a defining characteristic of nondiseased arteries, and abnormal endothelial NO release is both a marker of early atherosclerosis and a predictor of its progression and future events. Healthy coronaries respond to endothelial-dependent stressors with vasodilatation and increased coronary blood flow (CBF), but those with endothelial dysfunction respond with paradoxical vasoconstriction and reduced CBF. Recently, coronary MRI and isometric handgrip exercise (IHE) were reported to noninvasively quantify coronary endothelial function (CEF). However, it is not known whether the coronary response to IHE is actually mediated by NO and/or whether it is reproducible over weeks. To determine the contribution of NO, we studied the coronary response to IHE before and during infusion of N(G)-monomethyl-l-arginine (l-NMMA, 0.3 mg·kg(-1)·min(-1)), a NO-synthase inhibitor, in healthy volunteers. For reproducibility, we performed two MRI-IHE studies ∼8 wk apart in healthy subjects and patients with coronary artery disease (CAD). Changes from rest to IHE in coronary cross-sectional area (%CSA) and diastolic CBF (%CBF) were quantified. l-NMMA completely blocked normal coronary vasodilation during IHE [%CSA, 12.9 ± 2.5 (mean ± SE, placebo) vs. -0.3 ± 1.6% (l-NMMA); P < 0.001] and significantly blunted the increase in flow [%CBF, 47.7 ± 6.4 (placebo) vs. 10.6 ± 4.6% (l-NMMA); P < 0.001]. MRI-IHE measures obtained weeks apart strongly correlated for CSA (P < 0.0001) and CBF (P < 0.01). In conclusion, the normal human coronary vasoactive response to IHE is primarily mediated by NO. This noninvasive, reproducible MRI-IHE exam of NO-mediated CEF promises to be useful for studying CAD pathogenesis in low-risk populations and for evaluating translational strategies designed to alter CAD in patients.

Periodontal health and esthetic results in impacted teeth exposed by apically positioned flap technique

Objectives: This study evaluates the periodontal health status and the esthetic results of teeth subjected to orthodontic traction, after their exposure by an apically positioned flap. Study design: Fifteen patients were included in the study, ages between 11 and 28 years old. The fenestrated teeth and their homologous contralateral normally erupted teeth, used as control, were evaluated. Results: Statistically significant differences were found in the position of the gingival margin (p = 0.005), with an average distance between cemento-enamel junction (CEJ) and gingival margin of 2.47 mm (SD 1.19) in control teeth and of 1 mm (SD 1.31) in the operated teeth, and in the depth of palatal probing (p = 0.031), with 2.1 mm (SD 0.9) for the experimental teeth and 1.7 mm (SD 0.8) for the control teeth. The gingival index, the bleeding during probing and the probing depth did not show statistically significant differences. The patient"s subjective esthetic evaluation was more favorable for the control teeth in most of the cases. Conclusions: The surgical approach for the impacted teeth by means of the apically positioned flap resulted to be a predictable technique allowing the maintenance of the periodontal health on a long-term basis.

ICA as a preprocessing technique for classification

In this paper we propose the use of the independent component analysis (ICA) [1] technique for improving the classification rate of decision trees and multilayer perceptrons [2], [3]. The use of an ICA for the preprocessing stage, makes the structure of both classifiers simpler, and therefore improves the generalization properties. The hypothesis behind the proposed preprocessing is that an ICA analysis will transform the feature space into a space where the components are independent, and aligned to the axes and therefore will be more adapted to the way that a decision tree is constructed. Also the inference of the weights of a multilayer perceptron will be much easier because the gradient search in the weight space will follow independent trajectories. The result is that classifiers are less complex and on some databases the error rate is lower. This idea is also applicable to regression

La traçabilité, une technique de stigmatisation? Retour sur la problématisation de l'"hawala" dans le contexte antiterroriste

La surveillance financière contemporaine est toute entière associée à la volonté de tirer avantage des technologies de l'information et de la communication dans le but d'identifier et de suivre les flux de capitaux au nom de la lutte contre le blanchiment d'argent et le financement du terrorisme. Légitimées pour éviter tout blocage abrupt des mobilités, les techniques destinées à financer ces flux tendent à cadrer la circulation financière. Leur mise en place crée des obligations pour de nombreux acteurs économiques érigés en filtres protecteurs de l'architecture financière internationale. L'importance de cette logique de traçabilité a été amplifiée au lendemain des attentats du 11 septembre 2001, avec une stigmatisation accrue de tout ce qui n'est pas "traçable". L'objectif de cet article est précisément d'éclairer cette articulation entre promotion de la traçabilité et effets de stigmatisation dans un contexte bien précis de "panique morale" et de mise en priorité des problématiques antiterroristes. Le traitement réservé aux systèmes informels de transfert d'argent, souvent regroupés de manière abusive sous le terme <i>hawala</i>, en est l'exemple frappant.