Investigation of protein conformational stability employing a multimodal spectrometer

The conformational stability of proteins is typically investigated by use of a variety of biophysical measurements as a function of environmental stresses such as pH and temperature. Thus, multiple experiments are required on a variety of instruments, each providing information on a particular aspect of a protein's higher order structural integrity. These measurements typically require large sample quantities and long experimental times. In this study, a new methodology is described to obtain protein conformational stability data simultaneously, including UV absorption, light scattering, and near- and far-UV circular dichroism, by employing a multimodal spectrometer. Fluorescence spectral data are also collected on the same instrument, although not simultaneously. The method was developed by examining the thermal and pH stability of four model proteins. Results showed reproducible and accurate results from this single instrument, and data collection was rapid with minimal protein sample requirements. We illustrate the application of this method to the generation of empirical phase diagrams (EPDs) to better characterize the overall conformational stability of proteins. This new approach facilitates the rapid characterization of protein structure and stability in a single methodology, useful for analysis of unknown proteins as well as screening of solution conditions to optimize stability for protein therapeutic drug candidates.     

Dielectric,ferroelectric, magnetic and magnetoelectric properties of 0.1Ni0.8Zn0.2Fe2O4–0.9Pb1−3x/2SmxZr0.65Ti0.35O3 magnetoelectric composites

Composites having general formula 0.1Ni_0.8Zn_0.2Fe₂O₄–0.9Pb_1−3x/2Sm_xZr_0.65Ti_0.35O₃ with x=0, 0.01, 0.02 and 0.03 were synthesized by a conventional solid state reaction route. X-ray diffraction analysis was carried out to confirm the coexistence of individual phases and microstructural study was done by using a scanning electron microscope. Dielectric properties were studied as a function of temperature and frequency. To study ferroelectric and magnetic ordering in composite samples, P–E and M–H hysteresis loops were recorded respectively. Maximum magnetoelectric coupling coefficient of 22.5 mV/cm Oe was observed for sample with x=0.03. A significant improvement in dielectric, ferroelectric, piezoelectric and magnetoelectric properties was observed for Sm substitution.     

Parametric optimization of dry sliding wear and friction of germanium doped lead calcium titanate borosilicate glass ceramic

In this study, specific wear rate (SWR) and coefficient of friction (COF) of the synthesized samples in 55[(Pb_xCa_1?x)O.TiO₂]?44[2SiO₂.B₂O₃]?1Ge with (0 ≤ x ≤ 0.7 mol%) system of glass ceramics was optimized using Taguchi method. The ASTM standards were used for preparing the samples for friction and wear tests on a pin-on-disc tribometer. The glass ceramic samples were used as pin materials that slid against a disc made up of EN32 steel. For assessing the tribological properties of the glass ceramics, three control factors, viz. material-compositions with varying fraction of x (x = 0.0, 0.1, 0.3, 0.5 and 0.7 mol%), sliding speeds (2.61, 3.14, 3.66, 4.18 and 4.71 m/s) and loads (10, 15, 20, 25 and 30 N) were considered in an L₂₅ orthogonal array design. The optimum input parameters for the minimum SWR and COF were selected based on signal to noise ratios and main effect plots. Analysis of variance (ANOVA) revealed that the sliding speed and lead oxide content of the material are the most contributing factors on SWR and COF, respectively. The optimization for minimizing the SWR and COF was carried out and confirmed. The surface morphologies of the tested glass ceramic sample were studied using scanning electron microscope (SEM) and the elemental analysis of the samples was done using energy dispersive analysis of X-rays (EDAX). The Vickers hardness at the free surface of the glass ceramic samples increased up to 9.59 mol% of lead oxide with the maximum hardness of 23.59 GPa. The compressive strength of glass ceramic samples could reach up to 190 MPa.     

Linseed oil as a potential resource for bio-diesel: A review

The energy crisis contributed to the development of bio-diesel production. Petroleum, charcoal and natural gas sources are limited and will be exhausted by the next century. Thus, looking for alternative source of energy is of vital importance Vegetable oils are a renewable and potentially inexhaustible source of energy with an energetic content close to diesel fuel. In recent years, bio-diesel has become more attractive as an alternative fuels for diesel engine because of its environmental benefits and it is made from renewable resource. Since edible oil demand is higher than its domestic production; there is no possibility of diverting this oil for production of bio-diesel in India. Being a tropical country, India is rich in forest resources having a wide range of trees, which yield a significant quantity of oilseeds. India is importing crude petroleum & petroleum products from Gulf countries. Indian scientists searched for an alternate to diesel fuel to preserve global environment and to withstand economical crisis. This review paper describes the production of linseed oil, its properties, composition and future potential for bio-diesel. Linseed plant contains high amount of oil in its seeds which can be converted to bio-diesel. Fatty acid compositions of linseed reported in literature are provided in this review. In this study the properties of methyl ester of linseed oil are compared with the properties of fossil diesel. The objective of this review is to give an update on the linseed plant, the production of bio-diesel from the linseed oil and research attempts to improve the technology of converting linseed oil to bio-diesel and the fuel properties of linseed bio-diesel. The technological methods that can be used to produce bio-diesel are presented together with their advantage and disadvantages. Many other areas that need to be researched on linseed oil are pointed out in this review.     

A Novel Data Mining Approach for Analysis and Pattern Recognition of Active Fingerprinting Components

Wireless Personal Communications - Active fingerprinting is an effective penetration testing technique to know about vulnerability of hosts against security threats and network as a whole....     

Experimental and Numerical Investigations on Hydrodynamics of Nanofluid Flowing in Coiled Tubes

Abstract

A numerical model was developed to analyze the hydrodynamics of TiO₂-water nanofluids flowing through straight and coiled tubes in laminar flow regime. Pressure drop of nanofluid predicted from this model was validated with experiments for identical dimensions of tubes and process conditions. The velocity contours of flow in straight as well as coiled tube were examined. The present study revealed that there was 74% decrease in pressure drop when the straight tube diameter was increased from 0.003?m to 0.0072?m. There was 46–51% decrease in friction factor when curvature ratio (D_c/d_t) was increased from 7.54 to 12.24 for 200<De?<?850.     

Influence of calcium substitution on structural and electrical properties of substituted barium titanate

Ba_0.80−xCa_xPb_0.20Ti_0.90Zr_0.10O₃ ceramics (x = 0, 0.10 and 0.20) were synthesized by solid state reaction. Samples microstructure and dielectric, ferroelectric and piezoelectric properties were studied. Dielectric constant (?), coercive field (E_c), remanent polarization (P_r) and ratio of remanent to spontaneous polarization (P_r/P_s) were studied at different temperatures. Sample with x = 0.10 was found to have maximum and comparatively more stable P_r/P_s ratio over a wide temperature range. Dielectric loss was found to improve with increase in x whereas piezoelectric charge coefficient d₃₃ was found to decrease with increase in x.     

A variant of cyclic pursuit for target tracking applications: theory and implementation

This paper presents a variant of the cyclic pursuit strategy that can be used for target tracking applications. Cyclic pursuit has been extensively used in multi-agent systems for a variety of applications. In order to monitor a target point or to track a slowly moving vehicle, we propose to use a group of non-holonomic vehicles. At equilibrium, the vehicles form a rigid polygonal around the target while encircling it. Necessary conditions for the existence of equilibrium and the stability of equilibrium formations are analysed considering unicycle model of the vehicles. The strategy is then applied to miniature aerial vehicles (MAV) represented by 6-DOF dynamical model. Finally the results are verified in a hardware in-loop simulator in real time, which included all on-board electronics of the MAVs.