Investigating the effects of reduced size on the properties of ferroelectrics

A series of experiments has been undertaken to understand more about the fundamental origin of the thickness-induced permittivity collapse often observed in conventional thin film ferroelectric heterostructures. The various experiments are discussed, highlighting the eventual need to examine permittivity collapse in thin film single crystal material. It has been seen that dielectric collapse is not a direct consequence of reduced size, and neither is it a consequence of unavoidable physics associated with the ferroelectric-electrode boundary. Research on three-dimensional shape-constrained ferroelectrics, emphasizing self-assembled structures based on nanoporous alumina templates and on FIB-milled single crystals, is also presented, and appears to represent an exciting area for ongoing research.     

Acetylcholinesterase voltammetric biosensors based on carbon nanostructure-chitosan composite material for organophosphate pesticides

A sensitive biosensor for chloropyrifos (CPF), an organophosphorus pesticide, was developed by immobilizing acetylcholinesterase (AChE) through covalent bonding to an oxidized exfoliated graphite nanoplatelet (xGnPs)–chitosan cross-linked composite. Because of the increased surface area and the conductive properties of the nanomaterial, AChE developed a high affinity for acetylthiocholine (ATCI) and formed thiocholine with a fast response. The response of the sensor was a linear function of ATCI concentration in two segments, one from 0.005 to 0.039 mM and the second from 0.064 mM to 0.258 mM. The corresponding equation for the first range was i_p(A) = 2.26 × 10^? 5c + 4.39 × 10^? 7 (R² = 0.992) and the equation for the second was i_p(A) = 6.80 × 10^? 6c + 1.30 × 10^? 6 (R² = 1.000), with a detection limit of 1.58 × 10^? 10 M. The fabrication of the sensor was simple, the response was fast and the stability acceptable. This sensor has many potential applications, the foremost being in organophosphorus pesticides.     

A near-optimal Algorithm for H 8 identification of fixed order rational models

This paper presents a near-optimal algorithm for H     

Investigation on the non‐quasi‐static effect implementation for millimeter‐wave FET models

The present article analyzes in detail different intrinsic small‐signal models for transistors. Particular attention is devoted to the non‐quasi‐static effects, which play a crucial role at microwave and millimeter‐wave frequencies. The advantages and disadvantages of these different equivalent circuit topologies are analyzed from both theoretical and experimental standpoints. This study clearly proves that best choice among these model representations depends on the specific device technology besides the investigated frequency range. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Study on phenol adsorption from aqueous solutions on exfoliated graphitic nanoplatelets

In this study we report first data on exfoliated graphitic nanoplatelets (xGnPs) as a sorbent for phenol removal and preliminary evaluated the ability of different type of natural organic matter (NOM) to effectively disperse exfoliated graphitic nanoplatelets.     

Therapeutic death: A look at Oregon's law.

Oregon voters approved the first American statute authorizing physician-assisted suicide, the Oregon Death With Dignity Act, in 1994. The authors of this article identify some positive and negative psychological effects of laws such as Oregon's on patients. Generally, they conclude, on the basis of psychological theory and the available data, that laws such as Oregon's benefit patients psychologically. Undoubtedly, however, there exist important possible antitherapeutic effects on patients, and the authors hope that discussion of both therapeutic and antitherapeutic consequences will stimulate future research by social scientists in this area. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of solar radiation on the flavonol content in broccoli inflorescence

The effect of solar radiation on the quercetin and kaempferol contents in the inflorescence of three broccoli cultivars (‘Lord’, ‘Marathon’ and ‘Fiesta’) was investigated from 1999 to 2001. Great differences in the contents of both flavonols, dependent on growing time and cultivar, were found. Quercetin and kaempferol contents varied from 14.3 to 81.0 mg kg⁻¹ f.w. and from 35.9 to 213 mg kg⁻¹ f.w., respectively. Inflorescences of the cultivar ‘Lord’ were characterised by the highest mean content of quercetin and those of cultivar ‘Fiesta’ of kaempferol. The contents of both flavonols were highly positively correlated with total solar radiation in the period from planting to the harvest of broccoli inflorescences.     

Interfacial chemistry on carboxylate-functionalized monolayer assemblies

Deposition of trichlorosilanes with ester groups at their remote termini provides a convenient entry to carboxylic acid-bearing siloxane-anchored self-assembled monolayers. The de-esterification of these esters has been optimized to minimize monolayer damage, and their quantitative re-esterification provides clear evidence for the stability of these systems. Both the structure of the ester-terminated monolayer and its de-esterification/esterification chemistry can be easily monitored by FTIR-ATR measurements. This spectroscopic tool, together with a liquid cell that enables IR spectra to be measured in an aqueous environment, enables a detailed structural analysis of the carboxylic acid-bearing siloxane-anchored self-assembled monolayers and an assessment of their acid/base behavior (by in situ titration). The use of D₂O instead of H₂O for the in situ titration experiments also improves the available IR window. Both monomeric and dimeric/oligomeric acid groups are seen, and the relative ease of deprotonation of these various species can be directly monitored. Monomers of alkyl carboxylic acids that are hydrogen bonded only to surrounding water molecules have a pK_a = 4.9, while the pK_a for the aggregated molecules is 9.3. Similar behavior is seen for surface-bound benzoic acids, where the two pK_a values are 4.7 and 9.0. The influence of temperature on these structures and their chemistry has been explored to a limited extent as well. When the alkylcarboxylic acid system is cooled to 10 °C, the pK_a value for the acid monomers is reduced from 4.9 to 4.5 and increases from 9.3 to 10.3 for the aggregates.     

Surface-enhanced Raman scattering nanosensors for <Emphasis Type="Italic">in vivo</Emphasis> detection of nucleic acid targets in a large animal model

Although nanotechnology has led to important advances in in vitro diagnostics, the development of nanosensors for in vivo detection remains very challenging. Here, we demonstrated the proof-of-principle of in vivo detection of nucleic acid targets using a promising type of surface-enhanced Raman scattering (SERS) nanosensor implanted in the skin of a large animal model (pig). The in vivo nanosensor used in this study involves the “inverse molecular sentinel” detection scheme using plasmonics-active nanostars, which have tunable absorption bands in the near infrared region of the “tissue optical window”, rendering them efficient as an optical sensing platform for in vivo optical detection. Ex vivo measurements were also performed using human skin grafts to demonstrate the detection of SERS nanosensors through tissue. In this study, a new core–shell nanorattle probe with Raman reporters trapped between the core and shell was utilized as an internal standard system for self-calibration. These results illustrate the usefulness and translational potential of the SERS nanosensor for in vivo biosensing.

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