Making Existential-Unforgeable Signatures Strongly Unforgeable in the Quantum Random-Oracle Model

Strongly unforgeable signature schemes provide a more stringent security guarantee than the standard existential unforgeability. It requires that not only forging a signature on a new message is hard, it is infeasible as well to produce a new signature on a message for which the adversary has seen valid signatures before. Strongly unforgeable signatures are useful both in practice and as a building block in many cryptographic constructions. This work investigates a generic transformation that compiles any existential-unforgeable scheme into a strongly unforgeable one, which was proposed by Teranishi et al. and was proven in the classical random-oracle model. Our main contribution is showing that the transformation also works against quantum adversaries in the quantum random-oracle model. We develop proof techniques such as adaptively programming a quantum random-oracle in a new setting, which could be of independent interest. Applying the transformation to an existential-unforgeable signature scheme due to Cash et al., which can be shown to be quantum-secure assuming certain lattice problems are hard for quantum computers, we get an efficient quantum-secure strongly unforgeable signature scheme in the quantum random-oracle model.Comment: 15 pages, to appear in Proceedings TQC 201

Conducting polymer nanowires for multi-analyte chemiresistive sensing

A conducting polymer nanowire-based chemiresistive sensor array was developed for the liquid-phase multi-analyte detection. The ability to distinguish and quantify multiple chemical species with a single sensory device can be useful in many areas including food industry, pollution control, biosensors, and explosives detection. A polyaniline nanowire is a good candidate for use as a chemiresistive sensing material due to its large resistivity change and ease of synthesis. However the two most important issues in chemiresistive sensors are the reproducibility in sensing and the selectivity in chemical species. For improving the reproducibility in polyaniline-based chemiresistive sensing, a self-calibration mechanism was proposed. This method utilizes two unique properties of polyaniline: one is the rate of the conductivity decay upon repeated cycling of the electrochemical potential, and the other is the position of the second redox potential, both of which are pH-dependent. These two properties were minimally affected by the polyaniline’s inherent limitations, i.e. hysteresis and degradation, and therefore were effective in obtaining repeatable measurements. In order to enhance the selectivity, a catalyst-based selective detection was proposed. This method is based on the concept that the catalytic reaction between the species and the catalysts causes a local pH change near the polyaniline nanowire network which changes the resistance of the polymer. Finally, a sensor array consisting of polyaniline nanowire-based chemiresistors with each sensing element modified with a unique catalyst was implemented for multi-analyte sensing of ascorbic acid, dopamine, and hydrogen peroxide. Principal component algorithm was applied for the classification and semi-quantification of the chemical species

(2,2′-Bipyrid­yl)bis­[N,N-bis­(2-hydroxy­ethyl)dithio­carbamato-κ2 S,S′]cadmium(II)

The title compound, [Cd(C5H10NO2S2)2(C10H8N2)], features a trigonal-prismatic coordination geometry for the CdII ion, based on an N2S4 donor set defined by two chelating dithio­carbamate ligands and a 2,2′-bipyridyl ligand. In the crystal, extensive O—H⋯O hydrogen bonding results in the formation of 12-membered {⋯HO}6 synthons and one-dimensional supra­molecular chains with further O—H⋯S inter­actions providing additional stability to the linear chain with base vector [01]

AUTOMATION OF SIZING FOR EMBRYONIC STEM CELL AGGREGATES

INTRODUCTION Embryonic stem cells (ESCs) are derived from the inner cell mass of a blastocyst; ESCs are of significant importance to cell and tissue engineering due to their pluripotent status, the ability to form all cell types within the body [1]. Pluripotency is greatly valued in regenerative medicine by providing a potential cell source to restore function to damaged tissues. A large quantity of stem cells is required in order for a stem cell therapy to be successful. Previous works have focused on expanding stem cell populations through stirred suspension bioreactors [2,3]. Bioreactors provide considerable advantages when compared to static tissue culture flask, including ease of automation and monitoring of specific parameters such as oxygen consumption and pH. ESCs cultured in bioreactors grow in cell clumps called aggregates, as seen in Fig 1. These aggregates are sized throughout the culture period as a measure of growth and to assess mass transfer limitations. Commonly used methods to size aggregates are to use microscope images and software to manually determine the longest diameter and the orthogonal diameter. These methods are labour intensive and are susceptible to human error. To address common issues with current methods of aggregate sizing, this project focuses on automating aggregate sizing by developing a plugin for the image analysis software, ImageJ by the US National Institute of Health [4]. METHODS Through development of the ImageJ plugin a process of image filters and enhancements were used to adjust the aggregates within an image so that sizing can occur. Based on Hunt’s use of ImageJ to analyze ESC culture growth and differentiation [5] we were able to determine suitable filters to process our aggregate images. Obtaining orthogonal diameter for each aggregate was accomplished by modifying the particle analyzer in ImageJ. Dougherty’s Measure Roi plugin [6] formed the basis in developing a method to obtain the orthogonal diameter. DISCUSSION AND CONCLUSIONS By developing a plugin for ImageJ to automatically size aggregates we have developed methods to process aggregate images and have extended the particle analyzer to include a measurement for the orthogonal diameter. This allows for automation of the aggregate sizing process.   Future studies should assess the ability of using ImageJ to analyze and accurately size aggregates. The study should consider the application of different sets of image filters to increase accuracy of measurements. A comparison of manual aggregate sizing to automated aggregate sizing should be performed to ensure usability

Effects of tobacco smoking on human ocular smooth pursuit

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109900/1/cptclpt199725.pd