15 research outputs found

    Thinking-aloud about web navigation

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    A new algorithm for protecting aggregate business microdata via a remote system

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    Releasing business microdata is a challenging problem for many statistical agencies. Businesses with distinct continuous characteristics such as extremely high income could easily be identified while these businesses are normally included in surveys representing the population. In order to provide data users with useful statistics while maintaining confidentiality, some statistical agencies have developed online based tools to allow users to specify and request tables created from microdata. These tools only release perturbed cell values generated from automatic output perturbation algorithms in order to protect each underlying observation against various attacks, such as differencing attacks. An example of the perturbation algorithms has been proposed by Thompson et al. (2013). The algorithm focuses largely on reducing disclosure risks without addressing much on data utility. As a result, the algorithm has limitations, including a limited scope of applicable cells and uncontrolled utility loss. In this paper we introduce a new algorithm for generating perturbed cell values. As a comparison, The new algorithm allows more control over utility loss, while it could also achieve better utility-disclosure tradeoffs in many cases, and is conjectured to be applicable to a wider scope of cells

    Synthesis, radiolabeling, and pre-clinical evaluation of [44Sc]Sc-AAZTA conjugate PSMA inhibitor, a new tracer for high-efficiency imaging of prostate cancer

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    Purpose The aim of this work was to demonstrate the suitability of AAZTA conjugated to PSMA inhibitor (B28110) labeled with scandium-44 as a new PET tracer for diagnostic imaging of prostate cancer.Background Nowadays, scandium-44 has received significant attention as a potential radionuclide with favorable characteristics for PET applications. A polyaminopolycarboxylate heptadentate ligand based on a 1,4-diazepine scaffold (AAZTA) has been thoroughly studied as chelator for Gd3+ ions for MRI applications. The excellent results of the equilibrium, kinetic, and labeling studies led to a preliminary assessment of the in vitro and in vivo behavior of [Sc-44][Sc-(AAZTA)](-) and two derivatives, i.e., [Sc-44][Sc (CNAAZTA-BSA)] and [Sc-44][Sc (CNAAZTA-cRGDfK)].Results B28110 was synthesized by hybrid approach, combining solid-phase peptide synthesis (SPPS) and solution chemistry to obtain high purity (97%) product with an overall yield of 9%. Subsequently, the radioactive labeling was performed with scandium-44 produced from natural calcium target in cyclotron, in good radiochemical yields (RCY) under mild condition (pH 4, 298 K). Stability study in human plasma showed good RCP% of [Sc-44]Sc-B28110 up to 24 h (94.32%). In vivo PET/MRI imaging on LNCaP tumor-bearing mice showed high tracer accumulation in the tumor regions as early as 20 min post-injection. Ex vivo biodistribution studies confirmed that the accumulation of Sc-44-PSMA-617 was two-fold lower than that of the radiolabeled B28110 probes.Conclusions This work demonstrated the suitability of B28110 for the complexation with scandium-44 at room temperature and the high performance of the resulting new tracer based on AAZTA chelator for the diagnosis of prostate cancer using PET
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