P792: a rapid clearance blood pool agent for magnetic resonance imaging: preliminary results

An original MRI contrast agent, called P792, is described. P792 is a gadolinium macrocyclic compound based on a Gd-DOTA structure substituted by hydrophilic arms. The chemical structure of P792 has been optimized in order to provide (1) a high r₁ relaxivity in the clinical field for MRI: 29 mM⁻¹ x s⁻¹ at 60 MHz. (2) a high biocompatibility profile and (3) a high molecular volume: the apparent hydrodynamic volume of P792 is 125 times greater than that of Gd-DOTA. As a result of this high molecular volume, P792 presents an unusual pharmacokinetic profile, as it is a Rapid Clearance Blood Pool Agent (RCBPA) characterized by limited diffusion across the normal endothelium. The original pharmacokinetic properties of this RCBPA are expected to be well suited to MR coronary angiography, angiography, perfusion imaging (stress and rest), and permeability imaging (detection of ischemia and tumor grading). Further experimental imaging studies are ongoing to define the clinical value of this compound.     

L'Année Psychologique: History of the founding of a 100-year-old French journal.

The authors present the history of the founding of the French journal L'Année Psychologique. The names of T. Ribot (1839–1916), H. Beaunis (1830–1921), and A. Binet (1857–1911) are closely associated with the journal. Ribot's election to the chair of Experimental and Comparative Psychology at the Collège de France in 1888 marked the official emancipation of psychology in France. Because there was no laboratory associated with the chair, Beaunis, a physiological psychologist from Nancy, proposed to Ribot the creation of the first French laboratory of experimental psychology (1889). Under Beaunis's direction, this laboratory was established at the Sorbonne in Paris but was in fact dependent on another educational institution, L'Ecole Pratique des Hautes Etudes. In 1893 the laboratory's research was first published in a yearly journal named Travaux du Laboratoire de Psychologie Physiologique (2 volumes: 1893–1894). Binet, who joined the laboratory in 1891, was not satisfied by the form of this publication. With Beaunis's agreement, he then created L'Année Psychologique in 1894 to develop the reputation of the laboratory's research. The authors present the evolution and vicissitudes of the journal from 1895 to 1912, with a glance up to the present. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sources and occurrence of dacthal in the Canadian atmosphere

Dacthal is a herbicide that can undergo long-range atmospheric transport. Due to limited use in Canada, its occurrence in the Canadian environment is likely associated with transboundary flow from the United States where 100 times more dacthal is used. To investigate its atmospheric distribution and possible sources, two sampling strategies were applied. First, polyurethane foam-disk passive air samplers were deployed across the country from the spring to summer of 2004 and 2005. Results showed highest dacthal concentrations at two sites in southern Ontario (max: 50 pg m(-3)) and much lower concentrations in other agricultural regions across Canada. Second, daily high-volume air samples were collected at a field site in north Toronto (Downsview). Sampling at this site was triggered by real-time meteorological forecast models that indicated when air flow to the site originated in the United States. Two such events, one in late June and one in late September 2005, were sampled. In both cases, elevated dacthal concentrations were captured (e.g., up to 319 pg m(-3) in the June event) and they were well correlated with transboundary flow from the United States. Finally, the octanol--air partition coefficient (K(OA)) of dacthal and other current-use pesticides was measured. K(OA) was used to derive a particle--gas partitioning coefficient (K(p)) for dacthal (Log K(p) = -4.1), indicating that this compound should exist mainly in the gas phase.     

Potential risks of metal toxicity in contaminated sediments of Deûle river in northern France

The aim of this paper was to evaluate the potential sediment cumulative damage and toxicity due to metal contamination in a polluted zone of De?le river (in northern France) from nearby two smelters. Metal-enrichment factors and geoaccumulation indices measured with sediment depth revealed that--compared to background levels either in local reference soils or in world rivers sediments/suspended particulate matter--Cd contributed to the highest pollution levels, followed by Zn, Pb and to a much lesser extent Cu and Ni. A comparison of the vertical distribution of AVS (acid volatile sulfides), SEM (simultaneously extracted metals), TMC (total metal concentrations), TOC (total organic carbon) and interstitial water-metal concentrations in the sediment allowed us to highlight the extent of toxicity caused by Cd, Pb, Zn, Ni and Cu and to raise the possibility of their association with certain geochemical phases. To assess the actual environmental impacts of these metals in De?le river, numerical sediment quality guidelines were further used in the present work. Sedimentary Pb, Zn, and Cd contents largely exceeded PEC (probable effect concentration) values reported as consensus-based sediment quality guidelines for freshwater ecosystems. As for risks of toxicity from pore waters, metal concentrations reached their maxima at the surficial layers of the sediment (1-3 cm) and IWCTU (Interstitial Water Criteria Toxicity Unit) observed for Pb and to a lesser extent Cd, violated the corresponding water quality data recommended by USEPA.     

Development of a Zeolite/Polymer-Based Hydrogel Composite through Photopolymerization for 3D Printing Application

In recent years, hydrogels have been widely applied in daily life and industry. More and more fillers have been combined with hydrogel to broaden their fields of application and improve their mechanical properties. However, there are few works about zeolite-based hydrogel composites via photopolymerization. Hence, in this work, it is reported that the fabrication of hydrogel composites containing zeolite (FAU-13X ≈ 40 wt%) under mild photopolymerization conditions (visible LED light irradiation, at room temperature, under air, and without any monomer purification). Markedly, compared to pure hydrogel, the elastic modulus (G′) of hydrogel composite contains 10% FAU-13X increased by more than 100%. When the zeolite content reached 40%, the water swelling ratio in mass reached 120%, and that in volume remained at 150%. In addition, 3D patterns with flat surface are obtained through direct laser write as a lithography technique. This means these hydrogel composites can be applied in the field of water absorption materials and 3D printing.     

Acetylxylan-pheophorbide-a nanoparticles designed for tumor-targeted photodynamic therapy

The poor solubility of most photosensitizers (PS) hampers their practical use as clinical agents. Conjugation of PS with water-soluble nanoparticles has been often used to bypass this hurdle. We describe in this study the extraction of glucuronoacetylxylan from chestnut sawdust, the hemisynthesis of pheophorbide-a (Pha) and its covalent attachment to xylan. The resulting conjugates (xyl-Pha) spontaneously form water-soluble spherical nanoparticles (xyl-Pha NPs) ranging between 100 and 250 nm in diameter. Assayed against the HT-29 colorectal cancer cell line, xyl-Pha NPs exhibited a dose-dependent phototoxicity only when irradiated with red light.     

Constraint scores for semi-supervised feature selection: A comparative study

Recent feature selection scores using pairwise constraints (must-link and cannot-link) have shown better performances than the unsupervised methods and comparable to the supervised ones. However, these scores use only the pairwise constraints and ignore the available information brought by the unlabeled data. Moreover, these constraint scores strongly depend on the given must-link and cannot-link subsets built by the user. In this paper, we address these problems and propose a new semi-supervised constraint score that uses both pairwise constraints and local properties of the unlabeled data. Experiments using Kendall’s coefficient and accuracy rates, show that this new score is less sensitive to the given constraints than the previous scores while providing similar performances.