Electric field and charge distribution imaging with sub-micron resolution in an organic Thin-Film Transistor

Here we show how Stark spectroscopy, coupled with confocal microscopy, is able to directly map the electric field in an n-type Copper-Fluorinated Phthalocyanine Thin-Film Transistor (TFT) under different operating conditions. To this extent, we locally probe Electro-Reflectance, with a nominal spatial resolution better than 500 nm, exploiting the fact that the detected signal is directly proportional to the square of the local field on the probe volume. This electric field imaging technique has unique advantages because it is non-invasive, since it exploits low incident power and because it probes the existing field in the bulk rather than the surface. Combining the experimental data with numerical modeling, it is possible not only to reconstruct the space charge profile in the few-nanometer thick accumulation layer, but also to extract the AC electron mobility.     

Plasma Exosome Profile in ST-Elevation Myocardial Infarction Patients with and without Out-of-Hospital Cardiac Arrest

The identification of new biomarkers allowing an early and more accurate characterization of patients with ST-segment elevation myocardial infarction (STEMI) is still needed, and exosomes represent an attractive diagnostic tool in this context. However, the characterization of their protein cargo in relation to cardiovascular clinical manifestation is still lacking. To this end, 35 STEMI patients (17 experiencing resuscitated out-of-hospital cardiac arrest (OHCA-STEMI) and 18 uncomplicated) and 32 patients with chronic coronary syndrome (CCS) were enrolled. Plasma exosomes were characterized by the nanoparticle tracking analysis and Western blotting. Exosomes from STEMI patients displayed a higher concentration and size and a greater expression of platelet (GPIIb) and vascular endothelial (VE-cadherin) markers, but a similar amount of cardiac troponin compared to CCS. In addition, a difference in exosome expression of acute-phase proteins (ceruloplasmin, transthyretin and fibronectin) between STEMI and CCS patients was found. GPIIb and brain-associated marker PLP1 accurately discriminated between OHCA and uncomplicated STEMI. In conclusion, the exosome profile of STEMI patients has peculiar features that differentiate it from that of CCS patients, reflecting the pathophysiological mechanisms involved in STEMI. Additionally, the exosome expression of brain- and platelet-specific markers might allow the identification of patients experiencing ischemic brain injury in STEMI.     

Discriminative learning and recognition of image set classes using canonical correlations

We address the problem of comparing sets of images for object recognition, where the sets may represent variations in an object's appearance due to changing camera pose and lighting conditions. canonical correlations (also known as principal or canonical angles), which can be thought of as the angles between two d-dimensional subspaces, have recently attracted attention for image set matching. Canonical correlations offer many benefits in accuracy, efficiency, and robustness compared to the two main classical methods: parametric distribution-based and nonparametric sample-based matching of sets. Here, this is first demonstrated experimentally for reasonably sized data sets using existing methods exploiting canonical correlations. Motivated by their proven effectiveness, a novel discriminative learning method over sets is proposed for set classification. Specifically, inspired by classical linear discriminant analysis (LDA), we develop a linear discriminant function that maximizes the canonical correlations of within-class sets and minimizes the canonical correlations of between-class sets. Image sets transformed by the discriminant function are then compared by the canonical correlations. Classical orthogonal subspace method (OSM) is also investigated for the similar purpose and compared with the proposed method. The proposed method is evaluated on various object recognition problems using face image sets with arbitrary motion captured under different illuminations and image sets of 500 general objects taken at different views. The method is also applied to object category recognition using ETH-80 database. The proposed method is shown to outperform the state-of-the-art methods in terms of accuracy and efficiency     

Mixture of Trees Probabilistic Graphical Model for Video Segmentation

We present a novel mixture of trees probabilistic graphical model for semi-supervised video segmentation. Each component in this mixture represents a tree structured temporal linkage between super-pixels from the first to the last frame of a video sequence. We provide a variational inference scheme for this model to estimate super-pixel labels, their corresponding confidences, as well as the confidences in the temporal linkages. Our algorithm performs inference over full video volume which helps to avoid erroneous label propagation caused by using short time-window processing. In addition, our proposed inference scheme is very efficient both in terms of computational speed and use of RAM and so can be applied in real-time video segmentation scenarios. We bring out the pros and cons of our approach using extensive quantitative comparisons on challenging binary and multi-class video segmentation datasets.     

Overcoming shadows in 3-source photometric stereo

Light occlusions are one of the most significant difficulties of photometric stereo methods. When three or more images are available without occlusion, the local surface orientation is overdetermined so that shape can be computed and the shadowed pixels can be discarded. In this paper, we look at the challenging case when only two images are available without occlusion, leading to a one degree of freedom ambiguity per pixel in the local orientation. We show that, in the presence of noise, integrability alone cannot resolve this ambiguity and reconstruct the geometry in the shadowed regions. As the problem is ill-posed in the presence of noise, we describe two regularization schemes that improve the numerical performance of the algorithm while preserving the data. Finally, the paper describes how this theory applies in the framework of color photometric stereo where one is restricted to only three images and light occlusions are common. Experiments on synthetic and real image sequences are presented.     

Cross‐correlation‐based trans‐impedance amplifier for current noise measurements

This work proposes a cross‐correlation‐based trans‐impedance amplifier for current noise measurements in the low‐frequency range. The proposed solution is compared with the classical cross‐correlation trans‐impedance amplifier showing a lower background noise. Furthermore, a three‐step measurement method, based on the new trans‐impedance amplifier, is proposed to cancel the residual background noise. SPICE simulations and noise measurements performed on prototype circuits demonstrate the validity of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd.     

ISICS: A program for calculating K-, L- and M-shell cross sections from ECPSSR theory using a personal computer

A versatile and fast C-language program has been developed to exactly calculate ionization and x-ray production cross sections using the ECPSSR theory. All elements and any projectile can be selected for any range of energies and energy increments. Coulomb excitation form factors are numerically calculated in the program. Comparisons are presented between program calculations and those obtained by standard procedures from other sources. The program is available in compiled form and in source code for modification by the user. User options include selecting a relativistic calculation of the projectile ion velocity. Electron capture by the projectile is not incorporated into the program at this time.     

Bladder substitutes, bile acids and the risk of colorectal cancer: an experimental study

There is a large body of evidence relating the causation of colon cancer to bile acids. Using an animal model, we attempted to address the question, i.e., the incidences of carcinogenesis in the colon as consequences of resection of different bowel segments, predominantly employed in the construction of various forms of intestinal bladder substitutes. 60 male Wistar rats were operated. Group 1 served as control, in group 2, 20 cm of terminal ileum was resected, and rats in group 3 underwent resection of the distal 10 cm of the ileum and 7 cm of the proximal colon. All rats were killed 6 months after surgery and the colon was removed. After examination under 40-fold magnification, in the absence of tumors, 3 biopsies were performed at predetermined positions and underwent histological processing. Even if no tumor was found it would be incorrect to conclude that these results would have an appeasing relevance. The complex and highly different fecal bile acid profiles of the rat compared to man makes it impossible in this context to draw analogies between the rat model and human colonic carcinogenesis. Furthermore, 6 months of observation in the rat might be too short for 'spontaneous' colonic carcinogenesis. Nevertheless, there exists evidence from epidemiological studies to implicate bile acids as an etiological factor in the development and growth of colorectal cancer. Therefore, the importance of colorectal cancer in urologic surgery patients must be kept in perspective. In this direction, further studies are required besides the application of known appropriate preventive measures.     

Cloning and characterization of a developmentally regulated sea urchin cDNA encoding glutamine synthetase

A 2935-bp cDNA clone encoding glutamine synthetase (GS) was isolated from a cDNA library prepared from four-blastomere Paracentrotus lividus sea urchin embryos. The sequence consists of a 75-bp 5' untranslated region (5'-UTR) followed by a 1095-bp coding region corresponding to a 365-amino-acid (aa) protein, a 1747-bp 3'-UTR and a terminal 18-bp poly(A) tail. The encoded protein shows about 66% identical residues, as compared with human and lobster class-II GS. The sequence contains the Mn(2+)-binding aa and the highly conserved aa regions observed in other GS. Northern blot analyses show that the GS mRNA is present in the sea urchin egg and is developmentally regulated in the embryo.