Quantitative optical imaging of the pharmacokinetics of fluorescent-specific antibodies to tumor markers through tissuelike turbid media

Fluorescent optical imaging of tumors deep within tissue depends on specific binding of antibodies to the tumors' surface markers. These fluorescent antibodies propagating in the vicinity of the tumor can be attached to and (or) diffused away from it. We illustrate application of a new tool, based on the random-walk theory in turbid media, for extracting the pharmacokinetics of these fluorescent antibodies by data deconvolution, excluding the effect of upper turbid tissue layers.     

Interface Modifications of InAs Quantum‐Dots Solids and their Effects on FET Performance

InAs nanocrystals field‐effect transistors with an ON/OFF ratio of 10⁵ are reported. By tailoring the interface regions in the active layer step‐by‐step, the evolution of the ON/OFF ratio can be followed from approximately 5 all the way to around 10⁵. The formation of a semiconducting solid from colloidal nanocrystals is achieved through targeted design of the nanocrystal–nanocrystal interaction. The manipulation characteristics of the nanocrystal interfaces include the matrix surrounding the inorganic core, the interparticle distance, and the order of nanocrystals in the 3D array. Through careful analysis of device characteristics following each treatment, the effect of each on the physical properties of the films are able to be verified. The enhanced performance is related to interparticle spacing, reduction in sub‐gap states, and better electronic order (lower σ parameter). Films with enhanced charge transport qualities retain their quantum‐confined characteristics throughout the procedure, thus making them useful for optoelectronic applications.     

Elliptic boundary value problems for Bessel operators,with applications to anti-de Sitter spacetimes

This paper considers boundary value problems for a class of singular elliptic operators that appear naturally in the study of asymptotically anti-de Sitter (aAdS) spacetimes. These problems involve a singular Bessel operator acting in the normal direction. After formulating a Lopatinski?? condition, elliptic estimates are established for functions supported near the boundary. The Fredholm property follows from additional hypotheses in the interior. This paper provides a rigorous framework for mode analysis on aAdS spacetimes for a wide range of boundary conditions considered in the physics literature. Completeness of eigenfunctions for some Bessel operator pencils is shown.     

Sensing of Alkylating Agents Using Organic Field‐Effect Transistors

Alkylating agents are simple and reactive molecules that are commonly used in many and diverse fields, such as organic synthesis, medicine, and agriculture. Some highly reactive alkylating species are also being used as blister chemical warfare agents. The detection and identification of alkylating agent is not a trivial issue because of their high reactivity and simple structure. Here, a novel polythiophene derivative that is capable of reacting with alkylating agents is reported, along with its application in direct electrical sensing of alkylators using an organic field‐effect transistor, OFET, device. Upon reacting with alkylators, the OFET containing the new polythiophene analogue as its channel becomes conductive, and the gate effect is lost; this is in marked contrast to the response of the OFET to “innocent” vapors, such as alcohols and acetone. By following the drain–source current under gate bias, one can easily follow the processes of absorption of the analyte to the polythiophene channel and their subsequent reaction.     

On the angular error of intensity vector based direction of arrival estimation in reverberant sound fields

An acoustic vector sensor provides measurements of both the pressure and particle velocity of a sound field in which it is placed. These measurements are vectorial in nature and can be used for the purpose of source localization. A straightforward approach towards determining the direction of arrival (DOA) utilizes the acoustic intensity vector, which is the product of pressure and particle velocity. The accuracy of an intensity vector based DOA estimator in the presence of noise has been analyzed previously. In this paper, the effects of reverberation upon the accuracy of such a DOA estimator are examined. It is shown that particular realizations of reverberation differ from an ideal isotropically diffuse field, and induce an estimation bias which is dependent upon the room impulse responses (RIRs). The limited knowledge available pertaining the RIRs is expressed statistically by employing the diffuse qualities of reverberation to extend Polack's statistical RIR model. Expressions for evaluating the typical bias magnitude as well as its probability distribution are derived.     

Generating sensor signals in isotropic noise fields

Researchers in the signal processing community often require sensor signals that result from a spherically or cylindrically isotropic noise field for simulation purposes. Although it has been shown that these signals can be generated using a number of uncorrelated noise sources that are uniformly spaced on a sphere or cylinder, this method is seldom used in practice. In this paper algorithms that generate sensor signals of an arbitrary one- and three-dimensional array that result from a spherically or cylindrically isotropic noise field are developed. Furthermore, the influence of the number of noise sources on the accuracy of the generated sensor signals is investigated.     

Analysis of the power spectral deviation of the general transfer function GSC

In recent work, we considered a microphone array located in a reverberated room, where general transfer functions (TFs) relate the source signal and the microphones, for enhancing a speech signal contaminated by interference. It was shown that it is sufficient to use the ratio between the different TFs rather than the TFs themselves in order to implement the suggested algorithm. An unbiased estimate of the TFs ratios was obtained by exploiting the nonstationarity of the speech signal. In this correspondence, we present an analysis of a distortion indicator, namely power spectral density (PSD) deviation, imposed on the desired signal by our newly suggested transfer function generalized sidelobe canceller (TF-GSC) algorithm. It is well known that for speech signals, PSD deviation between the reconstructed signal and the original one is the main contribution for speech quality degradation. As we are mainly dealing with speech signals, we analyze the PSD deviation rather than the regular waveform distortion. The resulting expression depends on the TFs involved, the noise field, and the quality of estimation of the TF's ratios. For the latter dependency, we provide an approximated analysis of estimation procedure that is based on the signal's nanstationarity and explore its dependency on the actual speech signal and on the signal-to-noise ratio (SNR) level. The theoretical expression is then used to establish empirical evaluation of the PSD deviation for several TFs of interest, various noise fields, and a wide range of SNR levels. It is shown that only a minor amount of PSD deviation is imposed on the beamformer output. The analysis presented in this correspondence is in good agreement with the actual performance presented in the former TF-GSC paper.     

Maximum likelihood estimation of direction of arrival using an acoustic vector-sensor

A vector-sensor consisting of a monopole sensor collocated with orthogonally oriented dipole sensors is used for direction of arrival (DOA) estimation in the presence of an isotropic noise-field or internal device noise. A maximum likelihood (ML) DOA estimator is derived and subsequently shown to be a special case of DOA estimation by means of a search for the direction of maximum steered response power (SRP). The problem of SRP maximization with respect to a vector-sensor can be solved with a computationally inexpensive algorithm. The ML estimator achieves asymptotic efficiency and thus outperforms existing estimators with respect to the mean square angular error (MSAE) measure. The beampattern associated with the ML estimator is shown to be identical to that used by the minimum power distortionless response beamformer for the purpose of signal enhancement.     

Quasinormal Modes for Schwarzschild–AdS Black Holes: Exponential Convergence to the Real Axis

We study quasinormal modes for massive scalar fields in Schwarzschild–anti-de Sitter black holes. When the mass-squared is above the Breitenlohner–Freedman bound, we show that for large angular momenta, ?, there exist quasinormal modes with imaginary parts of size exp(??/C). We provide an asymptotic expansion for the real parts of the modes closest to the real axis and identify the vanishing of certain coefficients depending on the dimension.     

Flexible waveguides for Er-YAG laser radiation delivery

Flexible plastic waveguides (FPW) were devised for the delivery of Er-YAG laser radiation. The FPW characteristics were studied under various conditions. In vitro studies were carried out to explore the drilling procedure on extracted teeth and the FPW-tissue mutual effects. The results which were obtained proved that the FPW as a delivery device might be a substitute hand applicator for the pneumatic turbine for drilling in teeth