Combustion synthesis and characterization of highly crystalline single phase nickel ferrite nanoparticles

A combustion route of synthesizing highly crystalline single phase nickel ferrite (NiFe₂O₄) spinel nanoparticles using various amounts of dl-alanine as fuel has been reported in this paper. The role of the amount of fuel is found to be significant in the size control and phase purity of nano crystalline samples. The structural, thermal, morphological and magnetic studies have been carried out. XRD patterns reveal the formation of highly crystalline nano NiFe₂O₄ with high degree of phase purity when fuel concentration is maintained at 1 M and 2 M. FTIR spectra also prove the formation of pure nano NiFe₂O₄. The temperature and fuel effects are found to have strong influence on size, structural, and magnetic properties of materials. The magnetic measurements show that the nano NiFe₂O₄ samples exhibit soft ferromagnetism with the highest saturation magnetization Ms at room temperature as 42.53 emu/g.     

Assessment of expression of Leloir pathway genes in wild-type galactose-fermenting Streptococcus thermophilus by real-time PCR

In this study, four galactose-positive (Gal⁺) Streptococcus thermophilus strains viz. AJM, JM1, KM3 and AUKD8 and one galactose-negative (Gal^?) S. thermophilus NCDC 218 were used to characterize the organization of Leloir pathway genes using long-range PCR, and expression of these genes were studied using real-time PCR, in presence of different sugars. Long-range PCR results showed that both Gal⁺ and Gal^? isolates, the gal–lac gene order (galRKTEM–lacSZ), are conserved including the size of individual genes. The promoter sequence of the three Gal⁺ isolates (AJM, JM1 and KM3) possessed single base pair deletion at ?28 region of galR and C to T substitution at ?9 box galK region. In contrast, Gal⁺ AUKD8 had A to T substitution at preceding ?25 region of galR. The expression of galK and galM grown in the presence of galactose was significantly higher in case of AJM (30- and 7.6-fold, respectively), followed by KM3 and JM1. In addition, galR, galT and galE showed higher expression in galactose, than in lactose and glucose medium. This study gives a preliminary idea on Leloir pathway gene expression in wild Gal⁺ S. thermophilus, and further studies may throw more light on the role of gal–lac operon in galactose metabolism.     

Intimate culture of families in the early socialization of literacy.

The intimate family culture for early literacy socialization was documented for a socioculturally heterogeneous sample of 66 children enrolled in pre-kindergarten through third grade at public elementary schools in a large U.S. city. Parents were interviewed about 3 types of indexes of their family's intimate culture: the child's engagement in various literacy-related activities at home, the parents' orientation towards the significance of literacy for early child development, and the family's routines of dinnertime, reading aloud, and doing homework for school. Basic reading competencies were assessed with the Woodcock-Johnson Psychoeducational Battery--Tests of Achievement, Revised Papers. Multiple regression analysis found that a significant proportion of variance in the children's literacy development was predicted by each of the quantitative indexes of intimate family culture, leaving little or no additional variance that was due to family income or ethnicity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Engineered dimer interface mutants of triosephosphate isomerase: the role of inter-subunit interactions in enzyme function and stability

The role of inter-subunit interactions in maintaining optimal catalytic activity in triosephosphate isomerase (TIM) has been probed, using the Plasmodium falciparum enzyme as a model. Examination of subunit interface contacts in the crystal structures suggests that residue 75 (Thr, conserved) and residue 13 (Cys, variable) make the largest number of inter-subunit contacts. The mutants Cys13Asp (C13D) and Cys13Glu (C13E) have been constructed and display significant reduction in catalytic activity when compared with wild-type (WT) enzyme (～ 7.4-fold decrease in k(cat) for the C13D and ～ 3.3-fold for the C13E mutants). Analytical gel filtration demonstrates that the C13D mutant dissociates at concentrations <1.25 μM, whereas the WT and the C13E enzymes retain the dimeric structure. The order of stability of the mutants in the presence of chemical denaturants, like urea and guanidium chloride, is WT > Cys13Glu > Cys13Asp. Irreversible thermal precipitation temperatures follow the same order as well. Modeling studies establish that the Cys13Asp mutation is likely to cause a significantly greater structural perturbation than Cys13Glu. Analysis of sequence and structural data for TIMs from diverse sources suggests that residues 13 and 82 form a pair of proximal sites, in which a limited number of residue pairs may be accommodated.     

Kinetics of reaction between meta-substituted long chain alkyl phenols and formaldehyde

The reaction between formaldehyde and long chain alkyl phenols as cardanol and 3-pentadecylphenol is found to be of second order, when it is studied in dioxanater (1:1) system in presence of catalyst hydroxide sodium as at 28, 50 and 70°C. Individual methylols were separated and identified by thin layer chromatography. The long alkyl chain in the meta-position of the phenolic nuclei sterically hinders The reactivity of 2-position at 28°C, but at higher temperatures i. e. 50 and 70°C this position gets activated resulting in the formation of various methylols.     

A comparative study on particle�Cfluid interactions in micro and nanofluids of aluminium oxide

Stable dispersions of micro and nanosized Al₂O₃ particles in ethylene glycol are prepared with the aid of sonication. The temperature dependant acoustic properties such as ultrasonic velocity, adiabatic compressibility, attenuation and acoustic impedance are studied and reported in this paper. In microfluids the particle–fluid interaction is observed to decrease with increase of concentration of particles whereas in nanofluids it is observed to increase up to the critical concentration (0.6 Wt%) and above which the particle–particle interaction dominates due to agglomeration of particles. A range of concentration with significant particle–fluid interaction is identified for effective nanofluid applications.     

Energy efficient surveillance system using WVSN with reweighted sampling in modified fast Haar wavelet transform domain

Wireless visual sensor network (WVSN) consists of a large number of nodes that are capable of acquiring, compressing and transmitting images. Surveillance becomes a vital application area of WVSN as they can be deployed in various environments to monitor and collect information. The lifetime of the nodes in the network depends on the energy consumption. Hence in this paper, block compressed sensing (BCS) based image transmission technique that utilizes Energy based Reweighted sampling (ERWS) in Modified Fast Haar Wavelet Transform (MFHWT) domain is proposed to reduce energy consumption considerably. Sparse binary random matrix is used to acquire CS measurements in MFHWT domain. In addition, the proposed technique also maintains the image quality. The developed algorithm is applied and tested for a car parking lot monitoring system. It is evident from the simulation results that the proposed method achieves better PSNR values even for fewer measurements. Experimental analysis is performed using Atmega 128 processor of Mica mote in WinAVR by Atmel. The proposed method has approximately 85.5% lesser energy consumption than other Compressed Sensing (CS) methods. Lossless Entropy Coding is applied to the ERWS measurements and considerable reduction in number of transmitted bits is also achieved. The algorithm has also been tested in WINGZ mote in real time.     

Connecting Active‐Site Loop Conformations and Catalysis in Triosephosphate Isomerase: Insights from a Rare Variation at Residue 96 in the Plasmodial Enzyme

Despite extensive research into triosephosphate isomerases (TIMs), there exists a gap in understanding of the remarkable conjunction between catalytic loop‐6 (residues 166–176) movement and the conformational flip of Glu165 (catalytic base) upon substrate binding that primes the active site for efficient catalysis. The overwhelming occurrence of serine at position 96 (98 % of the 6277 unique TIM sequences), spatially proximal to E165 and the loop‐6 residues, raises questions about its role in catalysis. Notably, Plasmodium falciparum TIM has an extremely rare residue—phenylalanine—at this position whereas, curiously, the mutant F96S was catalytically defective. We have obtained insights into the influence of residue 96 on the loop‐6 conformational flip and E165 positioning by combining kinetic and structural studies on the PfTIM F96 mutants F96Y, F96A, F96S/S73A, and F96S/L167V with sequence conservation analysis and comparative analysis of the available apo and holo structures of the enzyme from diverse organisms.     

An Experimental Toolbox for Structure-Based Hit Discovery for P. aeruginosa FabF,a Promising Target for Antibiotics

FabF (3-oxoacyl-[acyl-carrier-protein] synthase 2), which catalyses the rate limiting condensation reaction in the fatty acid synthesis II pathway, is an attractive target for new antibiotics. Here, we focus on FabF from P. aeruginosa (PaFabF) as antibiotics against this pathogen are urgently needed. To facilitate exploration of this target we have set up an experimental toolbox consisting of binding assays using bio-layer interferometry (BLI) as well as saturation transfer difference (STD) and WaterLOGSY NMR in addition to robust conditions for structure determination. The suitability of the toolbox to support structure-based design of FabF inhibitors was demonstrated through the validation of hits obtained from virtual screening. Screening a library of almost 5 million compounds resulted in 6 compounds for which binding into the malonyl-binding site of FabF was shown. For one of the hits, the crystal structure in complex with PaFabF was determined. Based on the obtained binding mode, analogues were designed and synthesised, but affinity could not be improved. This work has laid the foundation for structure-based exploration of PaFabF.     

Time Triggered Hybrid Scheduler with Dynamic Frequency Scaling for Distributed Real Time Embedded Systems

Wireless Personal Communications - In this paper, the time triggered hybrid scheduler (TTH) is implemented in the distributed real time embedded systems along with the operation of dynamic...