Silicification and Biosilicification. Part 6. Poly-L-Histidine Mediated Synthesis of Silica at Neutral pH

Biosilicification results in the formation of ornate silica structures, which are seen in diatoms, sponges, grasses and other biological systems. Proteins have been isolated from diatoms, sponges and grasses that are proposed to be responsible for biosilicification and have been sequenced and/or some of the key amino acids identified. Studies of the amino acids primary sequence in these proteins suggest that lysine, histidine, arginine, cysteine, proline and serine probably play a role in biosilicification. Homopolymers of lysine, arginine and proline have been shown to form silica structures in vitro at (or close to) neutral pH. Here we report, for the first time, the ability of poly-L-histidine (PLHis) to form silica structures from a silica precursor at neutral pH. It was observed by scanning electron microscopy that PLHis facilitates the formation of silica spheres in the size range 150–200 nm and interconnected structures make up relatively smaller particles.     

Peer nomiations as a predictor of multistage promotions in a ramified organization.

Studied the validity of peer nominations (PNs) as a predictor of advancement in rank in the Israel Defense Forces on a population of 125 platoons encompassing 3897 soldiers. Results indicate that PNs obtained at early stages of training predicted promotion at several successive stages in the soldier's military career with a high degree of validity and correlations generally around .6 and .7. Predictions were valid for success within groups of different personnel, and with different purposes, and criteria for achievement. PNs were also found to contribute markedly to the predictive validity of conventional psychological screening measures, suggesting the value of combining psychometric and sociometric procedures for personnel selection. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estimation of parameters in multi-mode heat transfer problems using Bayesian inference – Effect of noise and a priori

Parameter estimation problems and heat source/flux reconstruction problems are some of the most frequently encountered inverse heat transfer problems. These problems find their application in many areas of science and engineering. The primary focus of this paper is on the heat transfer parameter estimation for a two-dimensional unsteady heat conduction problem with (a) convection boundary condition and (b) convection and radiation boundary condition. The paper demonstrates the effect of a priori model on the performance of the algorithm at different noise levels in the measured data. The inverse problem is solved using three different a priori models namely normal, log normal and uniform. The posterior PDF is sampled using the Metropolis–Hastings sampling algorithm. Both single-parameter estimation and multi-parameter estimation problems are addressed and the effects of corresponding a priori models are studied. It was found that the mean and maximum a posteriori estimates for thermal conductivity and the convection heat transfer coefficient were insensitive to the a priori model at all the considered noise levels for the single-parameter estimation problem. At high noise levels in the two-parameter estimation problem, the estimates for thermal conductivity and convection coefficient were sensitive to the a priori model. It was also found that the standard deviation of the samples was correlated to the error in estimation in the single-parameter estimation case. In three parameter estimation case, alternate solutions to the same problem were retrieved due to a strong correlation between the convection coefficient and the emissivity. However, a more informative a priori model could address this issue.     

Design of single-stage depressed collector for 42 GHz, 200 kW gyrotron

A single stage depressed collector has been designed to dissipate the spent electron energy of 45 keV. This results in an increase of overall efficiency of 42 GHz, 200 kW gyrotron from 33% to 57%. The design of depressed collector has taken into account the performance on several sectors such as maximum beam spread, minimum power dissipation including the effect of high voltage and thermal efficiency. Different computer codes have been used in order to design this particular collector. The simulated efficiency of the single stage depressed collector is 63%.     

Mechanical and swelling behavior of green nanocomposites of natural rubber latex and tubular shaped halloysite nano clay

Nanocomposites based on natural rubber latex as the matrix and naturally occurring tubular shaped nanoclay, halloysite nanotubes (HNTs) as the reinforcing phase were prepared through co‐coagulation method. XRD, morphology, mechanical, and solvent transport properties of the nanocomposites with special reference to weight percentage of nanoclay were analyzed and discussed in detail. Matrix–filler interaction was estimated from Kraus, Cunneen–Russell, and Lorentz–Park plots. Theoretical estimation of reinforcement effect revealed a better interaction between rubber and filler at lower concentration of filler. At higher loading properties decreased due to the formation of filler–filler networks than polymer–filler networks resulting in the reduction of aspect ratio of fillers. Properties of nanocomposites depend on the aspect ratio and volume fraction of reinforcing filler. Morphological analyses of the nanocomposites were done in detail from scanning electron micrographs. Theoretical modulus of nanocomposites was computed using different composite theories by varying the aspect ratio of filler and compared with experimental data. A good agreement between experimental and theoretical values was observed at lower concentration of filler. Solvent transport properties of nanocomposites were found to decrease at lower concentration of HNT because of the tortuosity of the path. POLYM. COMPOS., 37:602–611, 2016. © 2014 Society of Plastics Engineers     

Neurochemicals measured by 1H-MR spectroscopy: putative vulnerability biomarkers for obsessive compulsive disorder

Object

Obsessive compulsive disorder (OCD) is the fourth most common psychiatric disorder characterized by recurrent, intrusive thoughts and repetitive, ritualistic behaviors that are debilitating to the patient. Despite its high prevalence and the attendant morbidity, the pathophysiology of OCD remains unclear. Magnetic resonance spectroscopy (MRS) provides a noninvasive method to characterize the molecular biochemistry that may contribute to the pathophysiology of OCD. This study aimed to identify alterations in neurochemical measures that are specific to OCD using in vivo proton (¹H) MRS of the caudate nucleus, anterior cingulate cortex, and medial thalamus in these patients, and to identify their role as vulnerability markers by comparing them with the healthy first degree relatives of these patients and healthy controls.

Materials and methods

Appropriate psychometric instruments were applied in the study population followed by ¹H- MRS. The absolute neurochemical measures were quantified using a linear combination model.

Results

Significant differences in neurochemical measures were demonstrated in two of the three candidate regions (except the medial thalamus) between the three study groups.

Conclusions

Our results lend support to the neurodegenerative hypothesis of OCD, and also raise the possibility of exploring these neurochemical measures (as measured by MRS) as putative vulnerability biomarkers in OCD that may aid in early identification and devising early prevention or management strategies for the population vulnerable to OCD.     

Fava bean (Vicia faba L.) for food applications: From seed to ingredient processing and its effect on functional properties,antinutritional factors,flavor, and color

The food industry, along with the consumers, is interested in plant-based diet because of its health benefits and environmental sustainability. Vicia faba L. (V. faba) is a promising source of pulse proteins for the human diet and can yield potential nutritional and functional ingredients, namely, flours, concentrates, and isolates, which are relevant for industrial food applications. Different processes produce and functionalize V. faba ingredients relevant for industrial food applications, along with various alternatives within each unit operation used in their production. Processing modifies functional properties of the ingredients, which can occur by (i) changing in overall nutritional composition after processing steps and/or (ii) modifying the structure and conformation of protein and of other components present in the ingredients. Furthermore, V. faba limitations due to off-flavor, color, and antinutritional factors are influenced by ingredient production and processing that play a significant role in their consumer acceptability in foods. This review attempts to elucidate the influence of different ways of processing on the functional, sensory, and safety aspects of V. faba L. ingredients, highlighting the need for further research to better understand how the food industry could improve their utilization in the market.     

Implementation of a High Throughput Soft MIMO Detector on GPU

Multiple-input multiple-output (MIMO) significantly increases the throughput of a communication system by employing multiple antennas at the transmitter and the receiver. To extract maximum performance from a MIMO system, a computationally intensive search based detector is needed. To meet the challenge of MIMO detection, typical suboptimal MIMO detectors are ASIC or FPGA designs. We aim to show that a MIMO detector on Graphic processor unit (GPU), a low-cost parallel programmable co-processor, can achieve high throughput and can serve as an alternative to ASIC/FPGA designs. However, careful architecture aware software design is needed to leverage the performance offered by GPU. We propose a novel soft MIMO detection algorithm, multi-pass trellis traversal (MTT), and show that we can achieve ASIC/FPGA-like performance and handle different configurations in software on GPU. The proposed design can be used to accelerate wireless physical layer simulations and to offload MIMO detection processing in wireless testbed platforms.     

NCDP-plated CdSe film PEC cell studies

Thin films of CdSe grown by non-catalytic displacement plating (NCDP) are characterised electrochemically and photoelectrochemically in polysulphide electrolyte; using Cyclic Voltametry in dark and under intermittent illumination, band edges of NCDP-plated CdSe are located. A depletion width of 2 μm is calculated across the CdSeS²⁻/S₂²⁻ interface. Charge-transfer mechanism across this junction is discussed. Electrochemical and photoelectrochemical stabilities of NCDP-plated CdSe electrode are studied. Efficiency and fill factor of as-fabricated photoelectrochemical (PEC) cell are found to be 1.02% and 0.34, respectively.     

Sensitive Detection of Human Insulin Using a Designed Combined Pore Approach

A unique combined pore approach to the sensitive detection of human insulin is developed. Through a systematic study to understand the impact of pore size and surface chemistry of nanoporous materials on their enrichment and purification performance, the advantages of selected porous materials are integrated to enhance detection sensitivity in a unified two‐step process. In the first purification step, a rationally designed large pore material (ca. 100 nm in diameter) is chosen to repel the interferences from nontarget molecules. In the second enrichment step, a hydrophobically modified mesoporous material with a pore size of 5 nm is selected to enrich insulin molecules. A low detection limit of 0.05 ng mL^?1 in artificial urine is achieved by this advanced approach, similar to most antibody‐based analysis protocols. This designer approach is efficient and low cost, and thus has great potential in the sensitive detection of biomolecules in complex biological systems.