Interaction of cyclodextrins with human and bovine serum albumins: a combined spectroscopic and computational investigation

Interaction of cyclodextrins (CDs) with the two most abundant proteins, namely human serum albumin (HSA) and bovine serum albumin (BSA), has been investigated using steady-state and time-resolved fluorometric techniques, circular dichroism measurements and molecular docking simulation. The study reveals that the three CDs interact differently on the fluorescence and fluorescence lifetimes of the serum albumins. However, fluorescence anisotropy and circular dichroism are not affected. Depending on their size, different CDs bind to the serum albumins in different positions, resulting in changes in the spectral behaviour of the proteins. Docking study suggests the probable binding sites of the three CDs with the proteins. Combined experimental and computational studies imply that sufficiently high concentration of CDs causes loosening of the rigid structures of these transport proteins, although their secondary structures remain intact. Thus, CDs are found to be safe for the serum proteins from the structural point of view

Design and Modelling of a Novel Combustion Heat Exchanger for Household Heating

The present study is focused on the design and modelling of a novel Combustion Heat Exchanger (CHE), used for heating and hot water supplies in residential buildings. System design includes a combination of an efficient porous burner and heat exchangers. Combined with an Organic Rankine Cycle (ORC) and a Heat Pump (HP), it is meant to deliver higher energy efficiency as well as reduced greenhouse gas emissions. A numerical model has been developed in STAR-CCM+ to evaluate the design. Furthermore, system level heat transfer calculations were acquired to assist with the design process. A step by step approach was undertaken to investigate physical and chemical phenomena in the system. System dimensions, exchanger location and geometry, air/fuel ratio, porous media models, radiation and combustion were investigated along with different exchanger geometries. A novel spiral heat exchanger was introduced in addition to the common coil designs to exhibit both convection and radiation heat transfers. The results indicated that the exhibition of spiral heat exchanger would result in significantly enhanced heat transfer. Overall heat transfer coefficients of 4-5 times higher in comparison to coils could be expected for spiral exchangers. It was shown that radiation heat transfer accounts for a prominent share in the total heat transfer. Furthermore, the CHE could operate at a wide range of lean air/fuel ratios, enabling further decrease in greenhouse gas emissions. As the last part of the study, further investigations on the regular coil exchangers indicated that these exchangers could still be used with the design, but heat transfer enhancement is required to reduce the dimensions. Such enhancements were tested through shell geometry designs with improved results. Overall, the system shows a promising solution for further reduction of CO2 emissions while improving thermal efficiency

Tiny Blind Assistive Humanoid Robot

In today’s world, individuals show more enthusiasm for robotics and aim to depend upon humanoid robots for multiple purposes. It has implementations in a wide range of sectors such as- in atomic plants, house management, government foundations and even astro stations. Our research-based project is elucidating robotics with a tiny humanoid robot following the human structure to make gestures like strolling, dancing, and detecting objects near it. It has been achieved using Arduino Nano (Atmega 328P), Servo motors SG90 working on the conception of servomechanism and the Ultrasonic sensor to identify obstacles and restrain the Robot from going ahead. The aim is to fabricate a bigger humanoid robot that will serve our general public and make our life simpler. The Robot has eventual utilize in marketing, entertainment and helping the visually impaired to move from one place to another. This project can also be a great apparatus for future research works and alteration

Mutational Analysis of the Arf1•GTP/Arf GAP Interface Reveals an Arf1 Mutant that Selectively Affects the Arf GAP ASAP1

SummaryArf1 is a GTP binding protein that functions at a number of cellular sites to control membrane traffic and actin remodeling. Arf1 is regulated by site-specific GTPase-activating proteins (GAPs). The combined results of crystallographic and biochemical studies [1–3] have led to the proposal that Arf1 GAPs differ in the specific interface formed with Arf1. To test this hypothesis, we have used mutagenesis to examine the interaction of three Arf GAPs (ASAP1, AGAP1, and ArfGAP1) with switch 1, switch 2, and α helix3 of Arf1. The GAPs were similar in being affected by mutations in switch 1 and 2. However, effects of a mutation within α helix3 and specific mutations within switch 1 and 2 differed among the GAPs. The largest differences were observed with a change of isoleucine 46 to aspartate ([I46D]Arf1), which reduced ASAP1-induced catalysis by ∼10,000-fold but had a 3-fold effect on AGAP1. The reduction was due to an isolated effect on the catalytic rate, kcat. In vivo [I46D]Arf1 had no detectable effect on the Golgi apparatus but, instead, functioned as a constitutively active mutant in the cell periphery, affecting the localization of ASAP1 and paxillin. Based on our results, we conclude that the contribution of specific residues within switch 1 of Arf to binding and achieving a transition state toward GTP hydrolysis differs among Arf GAPs

Adaptation de maillage non structuré 3D pour les problèmes instationnaires.Application à la mécanique des fluides

Ce rapport aborde le thème de l'adaptation de maillage non structuré en trois dimensions pour les problèmes instationnaires et son application à la mécanique des fluides. On y montre en particulier que l'algorithme classique d'adaptation est inapproprié pour traiter ce type de problèmes. Par conséquent, on propose ici une autre approche basée sur un nouvel algorithme d'adaptation et sur une procédure d'intersection de métriques en temps, permettant de capturer de tels phénomènes. Plus précisément, une boucle spécifique est intégrée dans le schéma d'adaptation classique afin de résoudre un problème de point fixe transitoire pour le couple maillage-solution. L'estimateur d'erreur (géométrique) a posteriori anisotrope utilisé dans le schéma d'adaptation est basé sur une majoration de l'erreur d'interpolation. La métrique de calcul résultante est alors définie à l'aide du hessien de la solution. L'adaptation de maillage (surfacique et volumique) est basée sur une procédure visant à créer un maillage unité par rapport à la métrique spécifiée. Un exemple 3D est proposé pour illustrer l'efficacité de cette méthode

Electron multiplication CCD detector technology advancement for the WFIRST-AFTA coronagraph

The WFIRST-AFTA (Wide Field InfraRed Survey Telescope-Astrophysics Focused Telescope Asset) is a NASA space observatory. It will host two major astronomical instruments: a wide-field imager (WFI) to search for dark energy and carry out wide field near infrared (NIR) surveys, and a coronagraph instrument (CGI) to image and spectrally characterize extrasolar planets. In this paper, we discuss the work that has been carried out at JPL in advancing Electron Multiplying CCD (EMCCD) technology to higher flight maturity, with the goal of reaching a NASA technology readiness level of 6 (TRL-6) by early-to-mid 2016. The EMCCD has been baselined for both the coronagraph's imager and integral field spectrograph (IFS) based on its sub-electron noise performance at extremely low flux levels - the regime where the AFTA CGI will operate. We present results from a study that fully characterizes the beginning of life performance of the EMCCD. We also discuss, and present initial results from, a recent radiation test campaign that was designed and carried out to mimic the conditions of the WFIRST-AFTA space environment in an L2 orbit, where we sought to assess the sensor's end of life performance, particularly degradation of its charge transfer efficiency, in addition to other parameters such as dark current, electron multiplication gain, clock induced charge and read noise