A statistical 3-D pattern processing method for computer-aideddetection of polyps in CT colonography

Adenomatous polyps in the colon are believed to be the precursor to colorectal carcinoma, the second leading cause of cancer deaths in United States. In this paper, we propose a new method for computer-aided detection of polyps in computed tomography (CT) colonography (virtual colonoscopy), a technique in which polyps are imaged along the wall of the air-inflated, cleansed colon with X-ray CT. Initial work with computer aided detection has shown high sensitivity, but at a cost of too many false positives. We present a statistical approach that uses support vector machines to distinguish the differentiating characteristics of polyps and healthy tissue, and uses this information for the classification of the new cases. One of the main contributions of the paper is the new three-dimensional pattern processing approach, called random orthogonal shape sections method, which combines the information from many random images to generate reliable signatures of shape. The input to the proposed system is a collection of volume data from candidate polyps obtained by a high-sensitivity, low-specificity system that we developed previously. The results of our ten-fold cross-validation experiments show that, on the average, the system increases the specificity from 0.19 (0.35) to 0.69 (0.74) at a sensitivity level of 1.0 (0.95).     

Effect of hot water surface pasteurization of whole fruit on shelf life and quality of fresh-cut cantaloupe

ABSTRACT:  Cantaloupes are associated with recent outbreaks of foodborne illnesses and recalls. Therefore, new approaches are needed for sanitization of whole and cut fruit. In the present study, whole cantaloupes were submerged into water in the following 3 conditions: 10 °C water for 20 min (control), 20 ppm chlorine at 10 °C for 20 min, and 76 °C water for 3 min. Populations of microflora were measured on the rinds of the whole cantaloupes. Quality and microbial populations of fresh-cut cantaloupes prepared from whole fruit were analyzed after 1, 6, 8, 10, 13, 16, and 20 d of storage at 4 °C. The hot water significantly reduced both total plate count (TPC) and yeast and mold count on rind of whole fruits while chlorine or cold water wash did not result in a significant reduction of microbial population. Fresh-cut pieces prepared from hot water-treated cantaloupes had lower TPC than the other 2 treatments in the later storage periods (days 13 to 20) in 2 of 3 trials. The hot water treatment of whole fruits was inconsistent in reducing yeast and mold count of fresh-cut pieces. Soluble solids content, ascorbic acid content, fluid loss, and aroma and appearance scores were not consistently affected by either hot water or chlorine treatment. Our results suggested that hot water pasteurization of whole cantaloupes frequently resulted in lower TPCs of fresh-cut fruit during storage and did not negatively affect quality of fresh-cut cantaloupes.     

A new high-throughput screening method to determine multiple dyes in herbs and spices

The unauthorised addition of colours to herbs and spices is a recurrent issue affecting food business operators. Such a practice aims at improving food visual attractiveness, masking poor product quality, and/or compensating for natural colour variation with the ultimate goal to increase profits. To detect this fraud, a new LC–MS/MS method was developed for screening 58 dyes in both herbs and spices. This extended list of targets was established based on requirements from international spices organisations, past issues identified by web scouting and by notifications from the European Rapid Alert System for Food and Feed (RASFF). The method is intended to quickly detect fraudulent addition of dyes with Screening Target Concentrations ranging from 0.1 to 2.5 mg/kg. Validation was performed according to the European Community Reference Laboratories Residues Guidelines 20/1/2010. False positive and false negative rates were below 5% for all analytes and applicability of the method was further demonstrated by analysing 117 samples collected worldwide. None of the surveyed dyes was found in herbs (n = 28, 16 varieties) whereas 6% of spice samples (n = 89, 21 varieties) was found contaminated with one or two dyes at levels ranging from 0.12 to 255 mg/kg. Four out of the nine detected compounds have never been reported in the RASFF, thus demonstrating the usefulness of this analytical approach.     

On first-order Markov modeling for the Rayleigh fading channel

Previous models for the received signal amplitude of the flat-fading channel that use first-order finite-state Markov chains are examined. The stochastic properties of a proposed first-order model based on these models are examined. The limitations of using an information theoretic metric, which is sometimes used to justify a first-order Markov chain as a sufficient model for very slowly fading channels, are discussed. A simple method of qualitatively comparing autocorrelation functions is instead proposed. The usefulness of the first-order Markov chain in representing the flat-fading channel is examined by looking at two specific problems in wireless system applications that represent two disparate cases. The first case involves analysis over a short duration of time, relative to the inverse of the normalized Doppler frequency, while the second involves analysis over a long duration of time. Contrary to previous reports, the results indicate that first-order Markov chains are not generally suitable for very slowly fading channels. Rather, first-order Markov chains can be suitable for very slowly fading applications, which require analysis over only a short duration of time     

Performance Improvement of Non-Data-Aided Feedforward Symbol Timing Estimation Using the ?Better Than? Raised-Cosine Pulse

It is known that the "better than" raised-cosine pulse has several advantages over the conventional raised-cosine pulse. In addition to the advantages previously reported, this letter reports that the "better than" raised-cosine pulse enables better performance of symbol timing estimation than the raised-cosine pulse. Both Cramer-Rao lower bounds and simulations of practical synchronizers show the superiority of the new pulse. The performance gain can be as much as 3.4 dB for a practical system.     

Highly organized crystalline monolayer of a semi-fluorinated alkane on a solid substrate obtained by spin-coating

We have obtained a 40 nm parameter crystalline monolayer of a semifluorinated alkane on a silicon wafer using the spin-coating technique. Its structure, analyzed by atomic force microscopy (AFM), is identical to that recently observed at the air-water interface, showing the existence of hexagonal nanodomains, organized on a long range order hexagonal lattice of a few tens of nanometers lateral parameter. Considering AFM images published on films transferred by the usual Langmuir-Blodgett method, one can note that the monolayers form locally ordered rounded domains. With our procedure, the original highly organized large crystalline structure is recovered.     

In vitro characterization of purified human thymic dendritic cells infected with human immunodeficiency virus type 1

In the thymus, dendritic cells (DC) are functionally associated with thymocytes and are recognized to play a major role in the intrathymic differentiation of T cells. Several studies have previously investigated the role of DC during HIV-infection, but the status of thymic DC in HIV-1 pathogenesis remains unclear. In this study, we investigated the susceptibility of purified human thymic DC to HIV-1 infection in vitro. HIV-1 was not detected in cell-free supernatants collected from HIV-infected DC. However, these cultures were shown to transmit HIV-1 infection since coculture with permissive MT4 cells resulted in virus production. The exposure of DC in culture to HIV-1 was shown to promote severe DC morphological changes and killing. We also found that one or several heat labile soluble cytotoxic agents present in the HIV-1-infected DC supernatant mediated the killing of thymocytes. Our observations raise the possibility that (1) the HIV-1-induced DC killing, (2) the capacity of DC to transmit viral infection, and/or (3) the release of HIV-1-mediated cytotoxic agent(s) from DC may contribute to AIDS pathogenesis in vivo.     

On the performance of digital detectors with dependent samples

The asymptotic performances of three digital detectors operating with dependent samples are examined. Analytic expressions for the performances when the number of dependent samples M is large are obtained. Examples are also given which indicate how the performances vary with M. It is shown that the performances of hard-limiting detectors may be improved by processing more dependent samples. The amount of the hard-limiting loss that is recoverable depends upon the detector prefilter. A simple expression is derived which gives the irretrievable hard-limiting loss as a function of the noise autocorrelation,