Noncovalent functionalization of multi-walled carbon nanotubes by pyrene containing polymers

in Chemical Communications (2003), (23), 2904-2905

Multi-walled carbon nanotubes (MWNTs) have been solubilized in water and in various organic solvents by noncovalent side-wall functionalization by pyrene containing polymers.

Exploration des processus inhibiteurs dans le vieillissement normal

Poster (2003, December 05)

Influence de la variété sur le développement de mycosphaerella graminicola et sur les stratégies de protection fongicide chez le blé

in Conférence internationale sur les maladies des plantes (2003, December 03)

Mycosphaerella graminicola development is mainly influenced by climatic conditions; Rainrall, relative humidity and temperature are main para&meters taken in account in fungi development models and in ... [more ▼]

Mycosphaerella graminicola development is mainly influenced by climatic conditions; Rainrall, relative humidity and temperature are main para&meters taken in account in fungi development models and in decision support system for control of this wheat disease (Moreau and Maraite, 2000). However field trains have also shown that various crop parameters such variety susceptibility, have to be taken into consideration for optimum fungicide protection. [less ▲]

EnCOrE (Encyclopédie de Chimie Organique Electronique): an Original Way to Represent and Transfer Knowledge from Freshmen to Researchers in Organic Chemistry

in Electronic Workshops in Computing (2003, December 03)

EnCOrE is an original proposal which is expected to allow to share and transfer knowledge in organic chemistry. The system will use MIDES a software, with a peer-to-peer architecture, which will allow to ... [more ▼]

EnCOrE is an original proposal which is expected to allow to share and transfer knowledge in organic chemistry. The system will use MIDES a software, with a peer-to-peer architecture, which will allow to set up a technological and methodological frame to allow collaborative building of knowledge in between chemists. Learning GRID's services will help for Experimental electronic laboratory "LabCOrE" as well as for predictive computational tools. [less ▲]

Kinetic properties of the alpha(2) homo-oligomeric glycine receptor impairs a proper synaptic functioning

in Journal of Physiology-London (2003), 553(2), 369-386

Ionotropic glycine receptors (GlyRs) are present in the central nervous system well before the establishment of synaptic contacts. Immature nerve cells are known, at least in the spinal cord, to express ... [more ▼]

Ionotropic glycine receptors (GlyRs) are present in the central nervous system well before the establishment of synaptic contacts. Immature nerve cells are known, at least in the spinal cord, to express alpha(2) homomeric GlyRs, the properties of which are relatively unknown compared to those of the adult synaptic form of the GlyR (mainly alpha(1)/beta heteromeres). Here, the kinetics properties of GlyRs at the single-channel level have been recorded in real-time by means of the patch-clamp technique in the outside-out configuration coupled with an ultra-fast flow application system (< 100 µs). Recordings were performed on chinese hamster ovary (CHO) cells stably transfected with the a, GlyR subunit. We show that the onset, the relaxation and the desensitisation of α(2) homomeric GlyR-mediated currents are slower by one or two orders of magnitude compared to synaptic mature GlyRs and to other ligand-gated ionotropic channels involved in fast synaptic transmission. First latency analysis performed on single GlyR channels revealed that their slow activation time course was due to delayed openings. When synaptic release of glycine was mimicked (1 mM glycine; 1 ms pulse duration), the opening probability of α(2) homomeric GlyRs was low (P-o ≈ 0.1) when compared to mature synaptic GlyRs (P-o = 0.9). This low P-o is likely to be a direct consequence of the relatively slow activation kinetics of α(2) homomeric GlyRs when compared to the activation kinetics of mature α(1)/β GlyRs. Such slow kinetics suggest that embryonic α(2) homomeric GlyRs cannot be activated by fast neurotransmitter release at mature synapses but rather could be suited for a non-synaptic paracrine-like release of agonist, which is known to occur in the embryo. [less ▲]

Hot-cold plasma interactions and the generation of transient dayside sub-auroral proton precipitation

Conference (2003, December 01)

The IMAGE spacecraft obtained the first global images of the proton aurora. One of the discoveries from these images was proton precipitation equatorward of the nominal auroral oval. This precipitation ... [more ▼]

The IMAGE spacecraft obtained the first global images of the proton aurora. One of the discoveries from these images was proton precipitation equatorward of the nominal auroral oval. This precipitation can be observed for approximately 10 minutes immediately following a large solar wind pressure pulse. Various mechanisms have been proposed for producing this precipitation. Here, precipitation due to scattering from electromagnetic ion cyclotron (EMIC) waves is investigated using data from the IMAGE FUV and EUV imagers and in situ data from the Los Alamos geosynchronous spacecraft. In the proposed EMIC wave mechanism, the compression of the dayside magnetosphere enhances the growth rate of the wave instability. These waves scatter hot, ring current protons into the atmospheric loss cone, reducing the proton temperature anisotropy (the free energy source of the waves). Two features of the proton precipitation from these waves require explanation. First, the precipitation pattern may peak at any local time on the dayside between about 09 and 15. Second, the precipitation pattern has limited latitudinal extent (typically less than about 10 degrees) and is often separated from the main auroral oval. The local time peak in the precipitation pattern is related to the characteristics of the solar wind pressure pulse that causes EMIC wave growth. The separation of the precipitation pattern from the main auroral oval is related to properties of the hot and cold plasma within the magnetosphere that enhance EMIC wave growth. [less ▲]

Desarrollo de una estrategia para la optimización de la vacuna contra el virus de la diarrea viral bovina

Poster (2003, December 01)

Early activation of cardiac and renal endothelin systems in experimental heart failure

in American Journal of Physiology - Heart and Circulatory Physiology (2003), 285(6), 2482-2491

We investigated the time course of the expression of cardiac and renal endothelin systems in tachycardia-induced heart failure in dogs. Eleven beagles underwent rapid pacing at a progressively increased ... [more ▼]

We investigated the time course of the expression of cardiac and renal endothelin systems in tachycardia-induced heart failure in dogs. Eleven beagles underwent rapid pacing at a progressively increased rate over a period of 5 wk, with a weekly clinical examination, echocardiography, measurement of circulating and urinary endothelin-1 (ET-1), and myocardial and renal tissue biopsies. Real-time quantitative PCR was used for determinations of tissue prepro-ET-1 (ppET-1), ET-1-converting enzyme (ECE-1), and ETA and ETB receptor mRNA. Cardiac and renal tissue ET-1 contents were evaluated by immunostaining and measured by radioimmunoassay at autopsy. Rapid pacing caused a progressive increase in end-systolic and end-diastolic ventricular volumes (P<0.05) from week 2 together with a decrease in ejection fraction and in mean velocity of circumferential shortening (P<0.05) from week 1. These changes were tightly correlated to myocardial ppET-1 and renal ETA receptor mRNA and less so to myocardial ECE-1 mRNA, and they occurred before any increase in plasma and urinary ET-1 (P<0.05 from week 4) and clinical signs of heart failure. Renal ppET-1 did not change. Both cardiac and renal ET-1 peptide contents were increased at autopsy. We conclude that tachycardia-induced heart failure in dogs is characterized by an early activation of the cardiac and renal tissue endothelin systems, which occurs before any changes in circulating and urinary ET-1 and is closely related to altered ventricular function. [less ▲]

Identificación y caracterización de un nuevo elemento regulatorio que involucra al factor transcripcional E2F4 en la región U5 del LTR del virus de la leucosis bovina

Poster (2003, December 01)

IDENTIFICACIÓN Y CARACTERIZACIÓN DE UN NUEVO ELEMENTO REGULATORIO QUE INVOLUCRA AL FACTOR TRANSCRIPCIONAL E2F-4 EN LA REGIÓN U5 DEL LTR DEL VIRUS DE LA LEUCOSIS BOVINA S. Rodriguez1, C. Varone2, E ... [more ▼]

IDENTIFICACIÓN Y CARACTERIZACIÓN DE UN NUEVO ELEMENTO REGULATORIO QUE INVOLUCRA AL FACTOR TRANSCRIPCIONAL E2F-4 EN LA REGIÓN U5 DEL LTR DEL VIRUS DE LA LEUCOSIS BOVINA S. Rodriguez1, C. Varone2, E. Cánepa2, K. Trono1 1Instituto de Virología, CICVyA. INTA – Castelar. 2Cátedra de Biologia Molecular, Facultad de Ciencias Exactas, UBA. Buenos Aires, Argentina. El genoma del virus de la leucosis bovina (VLB), como todo retrovirus, presenta en ambos extremos zonas denominadas Long Terminal Repeats (LTRs) de importancia en la regulación de la transcripción. Estas regiones están organizadas en tres zonas llamadas U3, R y U5. La región U3 ha sido ampliamente estudiada y se sabe que contiene los principales sitios que regulan la transcripción viral. Sin embargo, poco se sabe de las regiones R y U5 aunque ha quedado demostrado que ambas zonas contienen asimismo secuencias estimulatorias. Con el objetivo de identificar y caracterizar nuevos elementos regulatorios, en este trabajo se ha llevado a cabo el estudio de secuencias de las regiones R y U5 del LTR 5´ de BLV. El análisis de patrones de reconocimiento de secuencias consenso para factores de transcripción celulares en estas regiones, reveló la presencia de 2 posibles elementos de unión para E2F, ambos en la zona U5, denominados E2F-A y E2F-B, respectivamente. Para analizar la capacidad de unión a factores celulares de las secuencias LTRs se llevaron a cabo ensayos de cambio en la movilidad electroforética (EMSA) y supershift utilizando extractos celulares obtenidos a partir de linfocitos bovinos y empleando los oligonucleótidos U51 y U52 como sondas, donde mapean los elementos E2FA y E2FB, respectivamente. Se observó retardo por la formación de complejos ribo-proteicos en ambos casos pero solo en el caso del complejo U51-E2F pudo ser identificado el factor E2F-4 utilizando anticuerpos específicos. En resumen, estos resultados permiten identificar un nuevo sitio para el factor de transcripción E2F-4 localizado en la región U5 del LTR 5´ de BLV. Este motivo constituye un nuevo elemento regulatorio involucrado en la actividad transcripcional de genes virales y celulares dirigida por los LTRs y podría jugar un rol importante en la replicación viral. [less ▲]

L’audiovisuel en Belgique francophone

Article for general public (2003)