Chiral discrimination of basic and hydrophobic molecules by chemical force spectroscopy

Chemical force spectroscopy (CFS) is becoming a powerful technique with which to measure intermolecular forces. The prime advantage over other techniques is the ability to map spatial distribution of ligands on the surface. We have used CFS to explore the binding force of a variety of different chiral molecules in order to understand more about the nature of what is a fundamental aspect of chemical biology and of central importance in pharmacology.     

Strengthening of alumina by cerium-zirconate (Ce2Zr2O7)

Composite powders of Al₂O₃ and 0 to 30 vol% Ce₂Zr₂O₇ are prepared by a hybrid sol-gel method using Al₂O₃ powders and a sol formed from Zr-alkoxide and cerium nitrate. All the Zr from the sol goes to form the cerium zirconate phase when the powders are calcined in N₂. Pressureless sintering in air at 1500°C yields composites with high density (98%). Maximum values of fracture toughness and strength, 6.5 MPa and 620 MPa respectively, (e.g. 3.5 MPa and 350 MPa for pure Al₂O₃) are obtained in 10 vol% Ce₂Zr₂O₇ composite sintered in air. The dominant mechanism for enhancement in K _IC is believed to be crack bridging. Crack bridging activity in the 10 vol% composite is found to be maximum and extends upto 190 m from the crack tip.     

Evaluation of high‐resolution and mobile display systems for digital radiology in dark and bright environments using human and computational observers

Abstract— As digital display systems replace film traditionally used for reading radiographic images, resource‐intensive acceptance testing must be performed to ensure that quality meets and maintains desired specifications. If machine observers can replace human readers, whose performances are highly variable, the results will be more consistent and less costly. To be effective, however, the automated observers must track human performance. An approach for a model observer, validated with human readers, for the evaluation of the visibility of low‐contrast small targets in high‐resolution and mobile displays under different ambient illumination, will be described. The displays were tested using CDMAM‐like digital phantoms containing disks of varying diameters and contrasts on a flat background. For this task, we find the best indicator of display performance to be the display's ability to represent small luminance contrast, not resolution or pixel size. The results confirm that high‐resolution systems perform better under low illumination while illuminance has a minor impact on the mobile‐display performance. Finally, the results show that the machine observer tracks the performance of human readers. Machine observers with proper validation can replace humans in the acceptance testing procedures, saving the testers both time and money.     

Rates of change of total ozone column and surface relative humidity: seasonal variations over Dum Dum (22° 38′ N, 88° 26′ E)

This article presents a study of the seasonal variability of the rate of change of total ozone column (TOC) and the rate of change of surface relative humidity (RH) over Dum Dum (22° 38′ N, 88° 26′ E) during different seasons of the period 1997–2005. The rate of formation of TOC was a maximum during the pre-monsoon and winter seasons and the rate of decrease of TOC was a maximum during the monsoon and post-monsoon seasons throughout the period of study. The rate of increase of surface RH was a maximum in the pre-monsoon season and the rate decreased during the other seasons. At the monsoon and post-monsoon seasons the rate of decrease of TOC increased with the rate of decrease of surface RH.     

Relative viscosity models and their application to capillary flow data of highly filled hard‐metal carbide powder compounds

The rheological behavior of highly filled polymer systems used in powder injection molding (PIM) technology strongly influences the final properties of the products. In this study, the capillary flow data of multi‐component polymer binders—based on polyethylene, paraffin, ethylene‐based copolymers, and polyethylene glycol—compounded with three various hard‐metal carbide powders were employed. The rheology of such highly filled (up to 50 vol%) multiphase systems is necessarily a complex phenomenon characterized by strain dependent, non‐Newtonian properties complicated by flow instabilities and yield. Over 15 mathematical models proposed for highly filled systems were tested, some of them calculating the maximum filler loading. Due to the complex structure of the filler (irregular shape, particle size distribution) and a multi‐component character of the binder, the applicability of these models varied with the powder‐binder systems studied. However, the particular values of maximum loadings are in good accordance with the predictions based on powder characteristics. Simple modification of Frankel‐Acrivos model to the systems containing unimodal hard‐metal carbide powders with particles of an irregular shape and broad particle size distribution gave precise agreement between experimental data and model prediction. POLYM. COMPOS., 26:29–36, 2005. © 2004 Society of Plastics Engineers.     

A novel quasi-oppositional chaotic antlion optimizer for global optimization

This paper proposes a novel quasi-oppositional chaotic antlion optimizer (ALO) (QOCALO) for solving global optimization problems. ALO is a population based algorithm motivated by the unique hunting behavior of antlions in nature and exhibits strong influence in solving global and engineering optimization problems. In the proposed QOCALO algorithm of the present work, the initial population is generated using the quasi-opposition based learning (QOBL) and the concept of QOBL based generation jumping is utilized inside the main searching strategy of the proposed algorithm. Utilization of QOBL ensures better convergence speed of the proposed algorithm and it also provides better exploration of the search space. Alongside the QOBL, a chaotic local search (CLS) is also incorporated in the proposed QOCALO algorithm. The CLS guides local search around the global best solution that provides better exploitation of the search space. Thus, a better trade-off between exploration and exploitation holds for the proposed algorithm which makes it robust. It is observed that the proposed algorithm offers better results than the original ALO in terms of solution quality and convergence speed. The proposed QOCALO algorithm is implemented and tested, successfully, on nineteen mathematical benchmark test functions of varying complexities and the experimental results are compared to those offered by the basic ALO and some other recently developed nature inspired algorithms. The efficacy of the proposed algorithm is further utilized to solve three real world engineering optimization problems viz. (a) the placement and sizing problem of distributed generators in radial distribution networks, (b) the congestion management problem in power transmission system and (c) the optimal design of pressure vessel.     

Multiobjective optimization for classifier ensemble and feature selection: an application to named entity recognition

In this paper, the concept of finding an appropriate classifier ensemble for named entity recognition is posed as a multiobjective optimization (MOO) problem. Our underlying assumption is that instead of searching for the best-fitting feature set for a particular classifier, ensembling of several classifiers those are trained using different feature representations could be a more fruitful approach, but it is crucial to determine the appropriate subset of classifiers that are most suitable for the ensemble. We use three heterogenous classifiers namely maximum entropy, conditional random field, and support vector machine in order to build a number of models depending upon the various representations of the available features. The proposed MOO-based ensemble technique is evaluated for three resource-constrained languages, namely Bengali, Hindi, and Telugu. Evaluation results yield the recall, precision, and F-measure values of 92.21, 92.72, and 92.46%, respectively, for Bengali; 97.07, 89.63, and 93.20%, respectively, for Hindi; and 80.79, 93.18, and 86.54%, respectively, for Telugu. We also evaluate our proposed technique with the CoNLL-2003 shared task English data sets that yield the recall, precision, and F-measure values of 89.72, 89.84, and 89.78%, respectively. Experimental results show that the classifier ensemble identified by our proposed MOO-based approach outperforms all the individual classifiers, two different conventional baseline ensembles, and the classifier ensemble identified by a single objective?Cbased approach. In a part of the paper, we formulate the problem of feature selection in any classifier under the MOO framework and show that our proposed classifier ensemble attains superior performance to it.     

Preparation and characterization of poly(vinyl alcohol)‐poly(vinyl pyrrolidone) blend: A biomaterial with latent medical applications

Aqueous solutions of poly(vinyl alcohol) and poly(vinyl pyrrolidone) are blended and films are produced by casting method with the further intention of being used as bio‐materials with latent medical application. Glutaraldehyde, 4,4′‐diazido‐2,2′‐stilbenedisulfonic acid disodium salt tetra‐hydrate are used as crosslinker agents, whereas lactic acid is the plasticizer in the blend. The obtained films are characterized by differential scanning calorimetry (DSC), mechanical properties, swelling and solubility behavior. DSC measurements show that the blends exhibit a single glass transition temperature indicating that they are miscible, even in the presence of the plasticizer and crosslinker agents. By the combination of all mentioned additives, a relevant enhancement of the swelling is observed, accompanied by a stabilization of the solubility during the tested time. Finally, mechanical properties show an appropriate performance in the studied parameters. As a consequence, the obtained films could be suitable for use as medium or long‐term implants. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013