55 research outputs found
New tecnologies for mobile mapping
This paper deals with the development of a low cost UAV (Unmanned Aerial Vehicle) devoted to early impact phase in case of environmental disasters, based on geomatics techniques. "Pelican" is a low-cost UAV prototype equipped with a photogrammetric payload that will allows reconnaissance operations in remote areas and rapid mapping production. Different digital sensors installed in the payload allow to acquire high resolution frame images. Furthermore a GPS/INS unit will enable an automated navigation (except take-off and landing). The project is supported by ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action), an association founded by Politecnico di Torino and SiTI (Istituto Superiore sui Sistemi Territoriali per l'Innovazione) in cooperation with WFP (World Food Programme) and some private and public organisms, with the main goal to carry on operational and research activities in the field of geomatics for analysis, evaluation and mitigation of natural and manmade hazards. The main technical features of the UAV and the on-board payload are detailed described in the first part of the paper. Furthermore first results of stereopairs orientation, case studies and further developments are presented
Obtención de Chalconas, Catalizada por Óxidos Mixtos de Al-Mg Modificadas con Metales Básicos
Los hidróxidos de doble capa son materiales pertenecientes a las arcillas aniónicas. Dichas arcillas pueden ser modificadas con determinados metales de manera de impartirles carácter básico para ser utilizadas en reacciones de química
fina. En este trabajo se presenta el estudio realizado a los hidróxidos de doble capa incorporados por el método de coprecipitación, con metales como el Zn, Ni, La y Ce. Dichos materiales presentaron buena estructura, área superficial y alta basicidad. En cuanto a la actividad catalítica, se estudió la reacción de condensación para la obtención de chalconas, obteniéndose conversiones por encima de 80% con altas selectividades y pureza del producto deseado
Automated Potentiometric Titrations in KCl/Water-Saturated Octanol: Method for Quantifying Factors Influencing Ion-Pair Partitioning
The knowledge base of factors influencing ion pair partitioning is very sparse, primarily because of the difficulty in determining accurate log PI values of desirable low molecular weight (MW) reference compounds. We have developed a potentiometric titration procedure in KCl/water-saturated octanol that provides a link to log PI through the thermodynamic cycle of ionization and partitioning. These titrations have the advantage of being independent of the magnitude of log P, while maintaining a reproducibility of a few hundredths of a log P in the calculated difference between log P neutral and log P ion pair (diff (log PN − I)). Simple model compounds can be used. The titration procedure is described in detail, along with a program for calculating pKa′′ values incorporating the ionization of water in octanol. Hydrogen bonding and steric factors have a greater influence on ion pairs than they do on neutral species, yet these factors are missing from current programs used to calculate log PI and log D. In contrast to the common assumption that diff (log PN − I) is the same for all amines, they can actually vary more than 3 log units, as in our examples. A major factor affecting log PI is the ability of water and the counterion to approach the charge center. Bulky substituents near the charge center have a negative influence on log PI. On the other hand, hydrogen bonding groups near the charge center have the opposite effect by lowering the free energy of the ion pair. The use of this titration method to determine substituent ion pair stabilization values (IPS) should bring about more accurate log D calculations and encourage species-specific QSAR involving log DN and log DI. This work also brings attention to the fascinating world of nature’s highly stabilized ion pairs
Autoinhibition of TBCB regulates EB1-mediated microtubule dynamics
Tubulin cofactors (TBCs) participate in the folding, dimerization, and dissociation pathways of the tubulin dimer. Among them, TBCB and TBCE are two CAP-Gly domain-containing proteins that interact and dissociate the tubulin dimer. Here we show how TBCB localizes at spindle and midzone microtubules during mitosis. Furthermore, the motif DEI/M-COO– present in TBCB, which is similar to the EEY/F-COO– element characteristic of EB proteins, CLIP-170, and α-tubulin, is required for TBCE–TBCB heterodimer formation and thus for tubulin dimer dissociation. This motif is responsible for TBCB autoinhibition, and our analysis suggests that TBCB is a monomer in solution. Mutants of TBCB lacking this motif are derepressed and induce microtubule depolymerization through an interaction with EB1 associated to microtubule tips. TBCB is also able to bind to the chaperonin complex CCT containing α-tubulin, suggesting that it could escort tubulin to facilitate its folding and dimerization, recycling or degradation
- …