Plant nanobionic materials with a giant temperature response mediated by pectin-Ca^(2+)

Conventional approaches to create biomaterials rely on reverse engineering of biological structures, on biomimicking, and on bioinspiration. Plant nanobionics is a recent approach to engineer new materials combining plant organelles with synthetic nanoparticles to enhance, for example, photosynthesis. Biological structures often outperform man-made materials. For example, higher plants sense temperature changes with high responsivity. However, these properties do not persist after cell death. Here, we permanently stabilize the temperature response of isolated plant cells adding carbon nanotubes (CNTs). Interconnecting cells, we create materials with an effective temperature coefficient of electrical resistance (TCR) of −1,730% K^(−1), ∼2 orders of magnitude higher than the best available sensors. This extreme temperature response is due to metal ions contained in the egg-box structure of the pectin backbone, lodged between cellulose microfibrils. The presence of a network of CNTs stabilizes the response of cells at high temperatures without decreasing the activation energy of the material. CNTs also increase the background conductivity, making these materials suitable elements for thermal and distance sensors

Enquête sur les pratiques documentaires des étudiants, chercheurs et enseignants-chercheurs de l\u27Université Pierre et Marie Curie (Paris 6) et Denis Diderot (Paris 7)

L\u27objectif de cette étude était non seulement d\u27interroger les pratiques documentaires au sens large (à la BIUSJ comme dans d\u27autres bibliothèques ou chez soi) des étudiants, enseignants et chercheurs, mais également d\u27apprécier le degré de satisfaction et les attentes concernant la BIUSJ de ceux qui la fréquentent comme de ceux qui ne la fréquentent pas

Enquête sur les pratiques documentaires des étudiants, chercheurs et enseignants-chercheurs de l\u27Université Pierre et Marie Curie et de l\u27Université Denis Diderot

En commandant une étude sur les pratiques documentaires des étudiants, des enseignants et des chercheurs en sciences des Universités de Paris 6 et Paris 7, le rectorat de Paris et la BIUSJ visent un double objectif. Il s’agit tout d’abord de procéder à un état des lieux concernant les attentes du public potentiel de la BIUSJ à un moment où l\u27Université de Paris VII construit de nouveaux locaux près de la Bibliothèque Nationale de France (BnF), dont une nouvelle bibliothèque. Il s’agissait aussi de contribuer à la connaissance des pratiques documentaires des étudiants, des enseignants et des chercheurs des disciplines scientifiques. En effet, les études existantes concernent soit les étudiants des disciplines littéraires (Lettres et Sciences humaines), soit les publics des grandes bibliothèques, comme la Bibliothèque nationale de France (BnF) et la Bibliothèque Publique d\u27Information (BPI), dont les étudiants représentent une part importante des usagers . Quant aux enseignants et aux chercheurs, les quelques études existantes, peu nombreuses, insistent sur l\u27importance des "collèges invisibles" , par le biais desquels l\u27information scientifique diffuse selon un mode essentiellement informel. En s’intéressant aux pratiques documentaires de la communauté des étudiants, des chercheurs et des enseignants en mathématiques, informatique, physique, chimie, biologie, sciences de la vie et de la terre du campus de Jussieu (Paris 6 et Paris 7), cette étude a pour ambition d’accroître les connaissances sur la place des grandes bibliothèques universitaires comme la BIUSJ dans l’enseignement et la recherche universitaires

Artificial membranes biomimicking pit vipers' thermal sensing

Artificial membranes that are sensitive to temperature are needed in robotics to augment interactions with humans and the environment, and in bioengineering to improve prosthetic limbs. Existing flexible sensors achieved sensitivities of <100 mK, albeit within narrow (<5 K) temperature ranges. Other flexible devices, working in wider temperature ranges, exhibit orders of magnitude poorer responses. However, much more versatile and temperature sensitive membranes are found in animals such as pit vipers, whose pit membranes have the highest sensitivity in nature and are used to locate warm-blooded preys at distance. Here, we show that pectin films mimic the sensing mechanism of pit membranes and parallel their record performance. These films map temperature on surfaces with a sensitivity of <10 mK in a wide temperature range (40 K) and detect warm bodies at distance

Dépenses culture-médias des ménages en France au milieu des années 2000 : une transformation structurelle

L’analyse des dépenses que les ménages français consacrent aux biens et aux services culturels et de communication permet de prendre la mesure des évolutions au cours des années 2000. Si elles ont diminué en 2006 par rapport à 2001 et ne représentent plus que 4 % du budget disponible contre 4,5 % cinq ans plus tôt, la structure des dépenses culture-médias s’est considérablement transformée. La numérisation des biens culturels a amplifié la transition vers une industrie de services. L’analyse confirme l’influence de l’âge, du niveau d’études, de la catégorie socioprofessionnelle et de la taille de la commune de résidence dans la part des dépenses qu’un ménage français consacre aux dépenses culturelles. Une approche typologique des dépenses identifie trois univers de consommation culturelle : la culture « traditionnelle », la culture de l’écran et la culture « jeune »

Chemical Composition and Biological Activities of Prangos ferulacea Essential Oils

Prangos ferulacea (L.) Lindl, which belongs to the Apiaceae family, is a species that mainly grows in the eastern Mediterranean region and in western Asia. It has been largely used in traditional medicine in several countries and it has been shown to possess several interesting biological properties. With the aim to provide new insights into the phytochemistry and pharmacology of this species, the essential oils of flowers and leaves from a local accession that grows in Sicily (Italy) and has not yet been previously studied were investigated. The chemical composition of both oils, obtained by hydrodistillation from the leaves and flowers, was evaluated by GC-MS. This analysis allowed us to identify a new chemotype, characterized by a large amount of (Z)-beta-ocimene. Furthermore, these essential oils have been tested for their possible antimicrobial and antioxidant activity. P. ferulacea essential oils exhibit moderate antimicrobial activity; in particular, the flower essential oil is harmful at low and wide spectrum concentrations. They also exhibit good antioxidant activity in vitro and in particular, it has been shown that the essential oils of the flowers and leaves of P. ferulacea caused a decrease in ROS and an increase in the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione S-transferase (GST) in OZ-stimulated PMNs. Therefore, these essential oils could be considered as promising candidates for pharmaceutical and nutraceutical preparations

Affinity of sulfamates and sulfamides to carbonic anhydrase II isoform: Experimental and molecular modeling approaches

Sixteen aromatic and aliphatic sulfamides and sulfamates were synthesized and tested in their inhibition to carbonic anhydrase CAII activity. The weaker inhibition pattern shown by sulfamides as compared to sulfamates is interpreted in this research by means of molecular modeling techniques, including known inhibitors (topiramate and its sulfamide cognate) in the analysis. The results nicely explain the origin of the inhibitory activity, which is not only related to positive interactions of the ligand with the active site residues but also to the solvation pattern characteristic of each ligand.Fil: Gavernet, Luciana. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Gonzales Funes, Jose Luis. Universidad Nacional de La Plata; ArgentinaFil: Bruno Blanch, Luis Enrique. Universidad Nacional de La Plata; ArgentinaFil: Estiu, Guillermina Lucia. University of Notre Dame-Indiana; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Maresca, Alfonso. Università degli Studi di Firenze; ItaliaFil: Supuran, Claudiu. Università degli Studi di Firenze; Itali

The significance of lipid composition for membrane activity: new concepts and ways of assessing function

In the last decade or so, it has been realised that membranes do not just have a lipid-bilayer structure in which proteins are embedded or with which they associate. Structures are dynamic and contain areas of heterogeneity which are vital for their formation. In this review, we discuss some of the ways in which these dynamic and heterogeneous structures have implications during stress and in relation to certain human diseases. A particular stress is that of temperature which may instigate adaptation in poikilotherms or appropriate defensive responses during fever in mammals. Recent data emphasise the role of membranes in sensing temperature changes and in controlling a regulatory loop with chaperone proteins. This loop seems to need the existence of specific membrane microdomains and also includes association of chaperone (heat stress) proteins with the membrane. The role of microdomains is then discussed further in relation to various human pathologies such as cardiovascular disease, cancer and neurodegenerative diseases. The concept of modifying membrane lipids (lipid therapy) as a means for treating such pathologies is then introduced. Examples are given when such methods have been shown to have benefit. In order to study membrane microheterogeneity in detail and to elucidate possible molecular mechanisms that account for alteration in membrane function, new methods are needed. In the second part of the review, we discuss ultra-sensitive and ultra-resolution imaging techniques. These include atomic force microscopy, single particle tracking, single particle tracing and various modern fluorescence methods. Finally, we deal with computing simulation of membrane systems. Such methods include coarse-grain techniques and Monte Carlo which offer further advances into molecular dynamics. As computational methods advance they will have more application by revealing the very subtle interactions that take place between the lipid and protein components of membranes – and which are so essential to their function