Background: PCR-based assays can improve clinical care, but they remain technically demanding and labor-intensive. We describe a new instrument, the GeneXpert ® , that performs automated nucleic acid isolation, reverse transcription, and fluorescence-based quantitative PCR in ϳ35 min. Methods: Yield and integrity of RNA isolated on the GeneXpert were compared with Qiagen-based extraction for parallel samples (5-m frozen tissue sections). The reproducibility of automated RNA isolation, reverse transcription, and quantitative PCR was determined by replicate (n ‫؍‬ 10) analysis of 10 tissues, using duplex (target and endogenous control) reverse transcription-PCR reactions for two gene combinations. The GeneXpert was then used to perform rapid analysis of lymph nodes from melanoma, breast cancer, and lung cancer patients and analysis of melanoma metastatic to the lung, primary lung adenocarcinoma, and healthy lung tissue. Results: On the GeneXpert, RNA was recovered in slightly over 6 min, and the yield was ϳ70% of that from parallel Qiagen reactions. The RNA integrity was comparable to that of Qiagen-isolated RNA as determined by gel electrophoresis. For the melanoma samples, the 95% prediction interval for the ⌬Ct for a new measurement was ؎1.54 cycles, and for breast cancer samples, the interval for a newly observed ⌬Ct was ؎1.40 cycles.

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In-network caching of content is a popular technique for eliminating redundant traffic from the network and improve the performance of network applications. In this paper we present a novel cooperative caching strategy to improve performance of in-network caches. Our cooperative scheme is composed of an admission policy for the incoming data and a content exchange protocol between neighbor network caches to improve the search zone. The admission policy enforces that a previously cached data is not unnecessary replicated in other caches, resulting in more space for new data. The content exchange protocol allows for exchange on cached data, increasing the hit rate for incoming requests. The benefits are twofold: first, we reduce the redundant content caching in the network, and second, we improve the hit rate by informing the content cached in the nearby caches. As a proof-of-concept, we have implemented a prototype and evaluated its performance using different large-scale topologies against standard non-cooperative caching algorithms. Our numerical results show that both admission and content exchange policies yield large performance gains over standard algorithms.

In this paper, we present a secure naming system to locate resources in information-centric networks. The main goal is to allow secure content retrieval from multiple unknown or untrusted sources. The proposal uses a new, flexible naming scheme that is backwards compatible with the current URL naming scheme and allows for independent content identification regardless of the routing, forwarding, and storage mechanisms by separating the source and location identification rules in the URI/URL authority fields. Some benefits of the new naming system include the opportunity to securely retrieve content from any source in the network, content mobility, content validation with the original source, and full backwards compatibility with the current naming system.

Abstract-In this paper we present an in-network caching architecture based on content routers to improve the traffic efficiency in the Internet. The main idea is to provide a forwarding fabric where data requests are forwarded towards the closest caches in the network path. Conversely, data chunks from the servers are cached in the content routers along the path, serving further data requests. In addition, content routers store a neighborhood mapping of available routers, leveraging resource discovery in the network proximity. Some benefits of the architecture include multi-source content retrieval, better traffic efficiency and gradual deployment. As proof-of-concept, we implemented a content router prototype and evaluated it in different scenarios comparing the bandwidth, latency and neighborhood search. The experimental results show that the content router can leverage multi-source content retrieval with bandwidth reduction without incurring in increased latency.

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Editor's Note.-Everyone who has taken the course in radiologic pathology at the Armed Forces Institute of Pathology (AFIP) remembers bringing beautifully illustrated cases for accession to the Institute. In recent years, the staff of the Department of Radiologic Pathology has judged the "best cases" by organ system, and recognition is given to the winners on the last day of the class. With each issue of RadioGraphics, one or more of these cases are published, written by the winning resident. Radiologicpathologic correlation is emphasized, and the causes of the imaging signs of various diseases are illustrated.