Synthesis and Characterization of Poly[bis(resorcinol monobenzoate) phosphazenes] and Poly[bis(resorcinol monobenzoate diethylamino) phosphazenes] and Their Self Assembly Behaviors

Poly[bis(resorcinol monobenzoate)phosphazenes] (PRMBP) and poly[bis(resorcinol monoben- zoate diethylamino)phosphazenes] (PRMBDEAP) were synthesized in two steps. In the first step, polydichlorophosphazenes (PDCP) were synthesized from hexachlorocyclotriphosphazenes (HCCP) via ring opening polymerization in the presence of AlCl₃ as a catalyst. In the second step, the chlorine atoms in PDCP were replaced with resorcinol monobenzoate and (or) diethylamine in a macromolecular substitution reaction. The structures of the polymers were elucidated by ¹H NMR, ³¹P NMR, and GPC. In addition, the self assembly behaviors of PRMBP and PRMBDEAP were investigated in different solvent using optical microscopy and SEM techniques. The SEM images showed that PRMBDEAP self assembled into star-like dendrimers comprising of open ended tubular arms.     

Structure,Characterization and Anti-Corrosion Activity of the New Metal–Organic Framework [Ag(qox)(4-ab)]

Yellow crystals of the metal–organic framework (MOF), [Ag(qox)(4-ab)] (1) were obtained at room temperature by the reaction of AgNO₃, quinoxaline (qox) and 4-amino benzoic acid (4-aba). A cluster molecule containing two silver atoms, two qox and two 4-ab ligands is considered the basic building block of the structure of 1. A 3D-network structure is created via H-bonds and π–π stacking. MOF 1 was tested as a corrosion inhibitor for C-steel in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance techniques. It was found that 1 is rich with electron donating groups and the π-systems exhibiting high inhibition efficiency. The adsorption of 1 obeyed the Freundlich adsorption isotherm. Polarization curves indicate that 1 is mixed-type inhibitor. Activation parameters were calculated and discussed. The results obtained from EIS and potentiodynamic polarization are in good agreement.     

Preserving objects in Markov Random Fields region growing image segmentation

This paper proposes an algorithm that preserves objects in Markov Random Fields (MRF) region growing based image segmentation. This is achieved by modifying the MRF energy minimization process so that it would penalize merging regions that have real edges in the boundary between them. Experimental results show that the integration of edge information increases the precision of the segmentation by ensuring the conservation of the objects contours during the region-growing process.     

Preparation,characterization and ex vivo–in vivo assessment of candesartan cilexetil nanocrystals via solid dispersion technique using an alkaline esterase activator carrier

The objective of this study was to improve candesartan cilexetil (CC) efficacy by formulating nanocrystals via solid dispersion (SD) technique using tromethamine (Tris). SD was prepared by solvent evaporation at different drug carrier ratios, evaluated for particle size, vitro dissolution studies, TEM, FTIR, and X-ray powder diffraction. Ex vivo, in vivo pharmacokinetic parameters were conducted on selected formulae compared to drug suspension and marketed product. Size analysis demonstrated formation of particles in the nanorange lower than 300?nm. A burst drug release followed by an improved dissolution was observed indicating instant formation of nanocrystals along with amorphization as confirmed by X-ray diffraction. FTIR studies suggested the absence of chemical interaction between Tris and CC. TEM revealed formation of irregular oval nanoparticles. SD-1:5 has higher apparent permeability coefficient compared to CC suspension. Furthermore, the pharmacokinetic results proved the ability of the formed nanoparticles to enhance the efficacy of CC compared to drug suspension and marketed product. In conclusion, using of Tris as alkaline esterase activator carrier could be a promising tool to bypass the controversial effect of esterase enzymes that may be a source for inter-individual variations affecting ester prodrug candidates’ efficacy.     

An Agent Model for the Resolution of Feature Conflicts in Telephony

Most telecommunication service providers resolve the feature interaction problem by providing specific instructions in their management software to handle scenarios where feature interaction may occur. This approach suffers from the complexity of the resulting code and the difficulty of adding new features to the system. Moreover, the system predefines the result of the resolution of the conflicting features and the end user has no means of choosing a different behavior, depending on the preferences of the user. In this paper we propose an agent-based architecture to detect and resolve feature interactions. Our system benefits from the flexibility and the semantic richness of policies and fuzzy logic to allow the end user to alter the behavior of the system, thus obtaining a more personalized service.     

Unraveling the Influence of Lanthanide Ions on Intra‐ and Inter‐Molecular Electronic Processes in Fe10Ln10 Nano‐Toruses

We investigated the electronic properties of the molecular magnetic nanotoruses [Fe^III ₁₀Ln^III ₁₀(Me‐tea)₁₀(Me‐teaH)₁₀(NO₃)₁₀], examining the dependence on the lanthanide (Ln) of both the intra and intermolecular electronic channels. Using femtosecond absorption spectroscopy we show that the intramolecular electronic channels follow a three‐step process, which involves vibrational cooling and crossing to shallow states, followed by recombination. A comparison with the energy gaps showed a relationship between trap efficiency and gaps, indicating that lanthanide ions create trap states to form excitons after photo‐excitation. Using high‐resistance transport measurements and scaling techniques, we investigated the intermolecular transport, demonstrating the dominant role of surface‐limited transport channels and the presence of different types of charge traps. The intermolecular transport properties can be rationalized in terms of a hopping model, and a connection is provided to the far‐IR spectroscopic properties. Comparison between intra and intermolecular processes highlights the role of the excited electronic states and the recombination processes, showing the influence of Kramers parity on the overall mobility.     

Measuring the cost of storage management

We study the cost of storage management for garbage-collected programs compiled with the Standard ML of New Jersey compiler. We show that the cost of storage management is not the same as the time spent garbage collecting. For many of the programs, the time spent garbage collecting is less than the time spent doing other storage-management tasks.This research was sponsored by the Defense Advanced Research Projects Agency, DoD, through ARPA Order 8313, and monitored by ESD/AVS under contract F19628-91-C-0168. Views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Defense Advanced Research Projects Agency or the United States Government. David Tarditi was also supported by an AT&T PhD Scholarship. Amer Diwan was also supported by National Science Foundation Grant CCR-9211272.     

Experimental investigation of an adsorptive thermal energy storage

A zeolite‐water adsorption module, which has been originally constructed for an adsorption heat pump, has been experimentally investigated as an adsorptive thermal energy storage unit. The adsorber/desorber heat exchanger contains 13.2 kg of zeolite 13X and is connected to an evaporator/condenser heat exchanger via a butterfly valve. The flow rate of the heat transfer fluid in the adsorber/desorber unit has been changed between 0.5 and 2.0 l min^?1, the inlet temperature to the evaporator between 10 and 40°C. It turned out that the higher the flow rate inside the adsorber/desorber unit the faster and more effective is the discharge of heat. However, at lower flow rates higher discharge temperatures are obtained. Storage capacities of 2.7 and 3.1 kWh have been measured at the evaporator inlet temperatures of 10 and 40°C, respectively, corresponding to thermal energy storage densities of 80 and 92 kWh m^?3 based on the volume of the adsorber unit. The measured maximum power density increases from 144 to 165 kWh m^?3 as the flow rate in the adsorber increases from 0.5 to 2 l min^?1. An internal insulation in form of a radiation shield around the adsorber heat exchanger is recommended to reduce the thermal losses of the adsorptive storage. Copyright © 2006 John Wiley & Sons, Ltd.     

Iterative cross section sequence graph for handwritten character segmentation.

The iterative cross section sequence graph (ICSSG) is an algorithm for handwritten character segmentation. It expands the cross section sequence graph concept by applying it iteratively at equally spaced thresholds. The iterative thresholding reduces the effect of information loss associated with image binarization. ICSSG preserves the characters' skeletal structure by preventing the interference of pixels that causes flooding of adjacent characters' segments. Improving the structural quality of the characters' skeleton facilitates better feature extraction and classification, which improves the overall performance of optical character recognition (OCR). Experimental results showed significant improvements in OCR recognition rates compared to other well-established segmentation algorithms.