Crotonaldehyde hydrogenation on Rh supported catalysts

The vapor-phase hydrogenation of crotonaldehyde on Rh supported catalysts has been studied. The effect of some variables of preparation in catalysts prepared by the sol-gel and impregnation methods on the surface and catalytic properties were analyzed. It was found, that the porosity of the support has a small effect on the selectivity to the unsaturated alcohol and the presence of partially reducible supports such as ZrO2 and TiO2, may increase the selectivity to crotyl alcohol via an enhancement of the polarization of the C=O bond as a result of surface decoration of the metal component. The presence of chlorine ions in the metal-support interfacial region, also allows, in a certain extension, a polarization of the carbonyl bond.Se estudió la hidrogenación en fase vapor de crotonaldehído sobre catalizadores de Rh soportados. Se analizó la influencia de diferentes variables de preparación de catalizadores obtenidos por el método sol-gel y por impregnación. Se encontró que la porosidad del soporte tiene sólo un pequeño efecto sobre la selectividad hacia el alcohol insaturado y que la presencia de soportes parcialmente reducibles como ZrO2 y TiO2 pueden incrementar la selectividad hacia el alcohol crotílico a través de un aumento de la polarización del enlace C=O como consecuencia de una decoración superficial del componente metálico. Adicionalmente, la presencia de iones cloruro en la interfase metal-soporte, también contribuyen en alguna medida a la polarización del enlace carbonílico.The authors thank CONICYT (Chile, FONDECYT Grants 1980345 and 2990065 and CSIC-CONICYT Collaboration Program) for their financial support.Peer reviewe

Coupling the Cardiac Voltage-Gated Sodium Channel to Channelrhodopsin-2 Generates Novel Optical Switches for Action Potential Studies

Voltage-gated sodium (Na + ) channels respond to short membrane depolarization with conformational changes leading to pore opening, Na + influx, and action potential (AP) upstroke. In the present study, we coupled channelrhodopsin-2 (ChR2), the key ion channel in optogenetics, directly to the cardiac voltage-gated Na + channel (Na v 1.5). Fusion constructs were expressed in Xenopus laevis oocytes, and electrophysiological recordings were performed by the two-microelectrode technique. Heteromeric channels retained both typical Na v 1.5 kinetics and light-sensitive ChR2 properties. Switching to the current-clamp mode and applying short blue-light pulses resulted either in subthreshold depolarization or in a rapid change of membrane polarity typically seen in APs of excitable cells. To study the effect of individual K + channels on the AP shape, we co-expressed either K v 1.2 or hERG with one of the Na v 1.5-ChR2 fusions. As expected, both delayed rectifier K + channels shortened AP duration significantly. K v 1.2 currents remarkably accelerated initial repolarization, whereas hERG channel activity efficiently restored the resting membrane potential. Finally, we investigated the effect of the LQT3 deletion mutant ΔKPQ on the AP shape and noticed an extremely prolonged AP duration that was directly correlated to the size of the non-inactivating Na + current fraction. In conclusion, coupling of ChR2 to a voltage-gated Na + channel generates optical switches that are useful for studying the effect of individual ion channels on the AP shape. Moreover, our novel optogenetic approach provides the potential for an application in pharmacology and optogenetic tissue-engineering

Блок измерения объёма подземных полостей в горнодобывающей промышленности

Выпускная квалификационная работа 77 с., 13 рис., 23 табл., 19 источника, 2 прил. Объектом исследования является блок измерения объема подземных полостей в горнодобывающей промышленности. Цель работы: разработка блока измерения объема подземных полостей в горнодобывающей промышленности. В процессе исследования проводились: литературный обзор, разработка структурной и принципиальной схем устройства, разработка алгоритма вычисления объема фигур неправильной формы, написание программы для микроконтроллера. В результате исследования: был спроектирован блок измерения объема подземных полостей. Основные конструктивные, технологические и технико-эксплуатационные характеристики: Режим работы – непрерывный;Final qualifying work 77 p., 13 fig., 23 tab., 19 sources, 2 adj. The object of this study is to measure the volume flow of underground cavities in the mining industry. Objective: Development of unit volume measurement of underground cavities in the mining industry. The study was conducted with a literature review, the development of the structural and fundamental unit circuits, the development of the algorithm for calculating the volume of irregularly shaped pieces, writing a program for the microcontroller. As a result of the study: it was designed unit measuring the volume of underground cavities. The basic constructive, technological and technical and operational characteristics: operating mode - continuous

Verification of Conjugate Heat Transfer Models in a Closed Volume with Radiative Heat Source

The results of verification of mathematical model of convective-conductive heat transfer in a closed volume with a thermally conductive enclosing structures are presented. Experiments were carried out to determine the temperature of floor premises in the working conditions of radiant heating systems. Comparison of mathematical modelling of temperature fields and experiments showed their good agreement. It is concluded that the mathematical model of conjugate heat transfers in the air cavity with a heat-conducting and heat-retaining walls correspond to the real process of formation of temperature fields in premises with gas infrared heaters system

Functional domains in the bacteriophage ø29 terminal protein for interaction with the ø29 DNA polymerase and with DNA

Deletion mutants at the amino- and carboxyl-ends of the ø29 terminal protein, as well as internal deletion and substitution mutants, whose ability to prime the initiation of ø29 DNA replication was affected to different extent, have been assayed for their capacity to interact with DNA or with the ø29 DNA polymerase. One DNA binding domain at the amino end of the terminal protein has been mapped. Two regions involved in the binding to the DNA polymerase, an internal region near the amino-terminus and a carboxyl-terminal one, have been also identified. Interaction with both DNA and ø29 DNA polymerase are required to led to the formation of terminal protein-dAMP initiation complex to start ø29 DNA replication.Peer reviewe