Multimedia Content Distribution in Hybrid Wireless Networks using Weighted Clustering

Fixed infrastructured networks naturally support centralized approaches for group management and information provisioning. Contrary to infrastructured networks, in multi-hop ad-hoc networks each node acts as a router as well as sender and receiver. Some applications, however, requires hierarchical arrangements that-for practical reasons-has to be done locally and self-organized. An additional challenge is to deal with mobility that causes permanent network partitioning and re-organizations. Technically, these problems can be tackled by providing additional uplinks to a backbone network, which can be used to access resources in the Internet as well as to inter-link multiple ad-hoc network partitions, creating a hybrid wireless network. In this paper, we present a prototypically implemented hybrid wireless network system optimized for multimedia content distribution. To efficiently manage the ad-hoc communicating devices a weighted clustering algorithm is introduced. The proposed localized algorithm deals with mobility, but does not require geographical information or distances.Comment: 2nd ACM Workshop on Wireless Multimedia Networking and Performance Modeling 2006 (ISBN 1-59593-485

HyCast-Podcast Discovery in Mobile Networks

Podcasts are a popular way to provide multimedia information about certain topics. A multitude of podcast servers exist in the Internet, allowing people to subscribe to them. Typically, podcasts are downloaded onto desktop computers and copied on mobile devices to be played while being on the move. In this paper, we extend the idea of podcasts, making them available in mobile network environments. In particular, HyCast does not rely on central podcast directories. Instead, HyCast also allows discovering, subscribing to, and downloading podcasts and episodes in the local neighborhood. For the dissemination of podcast information, we introduce and evaluate two different strategies. One is based on peer-to-peer communication between one-hop neighbors. The second one employs clustering to reduce the overhead of the podcast information dissemination

Stabilizing cluster structures in mobile networks for OLSR and WCPD as Basis for Service Discovery

International audienceService discovery is one of the most fundamental building blocks of self-organization. While mature approaches exist in the realm of fixed networks, they are not directly applicable in the context of MANETs. We investigate and compare two different protocols as basis for service discovery, namely OLSR and WCPD. OLSR is a proactive routing protocol while WCPD is a path discovery protocol integrating node and link stability criteria. Two conflicting objectives of service discovery are the coverage of service queries together with the required bandwidth. Simulations are performed based on a setting in a city center with human mobility. We show that OLSR outperforms WCPD in terms of coverage. Due to its proactive nature, however, bandwidth consumption is high. WCPD on the other hand is much more bandwidth efficient, but at the cost of lower coverage. Finally, we motivate employing OLSR on top of an overlay topology maintained by WCPD. This fosters stability while reducing overhead and keeping coverage high. As a first step towards a hybrid protocol, we aim at increasing the stability of the communication paths. To do so, an adaptive approach is used, which increases the robustness of the network topology structures

OLSR and WCPD as Basis for Service Discovery in MANETs

ISBN : 978-0-7695-3367-4International audienceService discovery is one of the most fundamental building blocks of self-organization. While mature approaches exist in the realm of fixed networks, they are not directly applicable in the context of MANETs. We investigate and compare two different protocols as basis for service discovery, namely OLSR and WCPD. OLSR is a proactive routing protocol while WCPD is a path discovery protocol integrating node and link stability criteria. Two conflicting objectives of service discovery are the coverage of service queries together with the required bandwidth. Simulations are performed based on a setting in a city center with human mobility. We show that OLSR outperforms WCPD in terms of coverage. Due to its proactive nature, however, bandwidth consumption is high. WCPD on the other hand is much more bandwidth efficient, but at the cost of lower coverage.Finally, we motivate employing OLSR on top of an overlay topology maintained by WCPD. This fosters stability while reducing overhead and keeping coverage high

An integrative genomic approach reveals coordinated expression of intronic miR-335, miR-342, and miR-561 with deregulated host genes in multiple myeloma

<p>Abstract</p> <p>Background</p> <p>The role of microRNAs (miRNAs) in multiple myeloma (MM) has yet to be fully elucidated. To identify miRNAs that are potentially deregulated in MM, we investigated those mapping within transcription units, based on evidence that intronic miRNAs are frequently coexpressed with their host genes. To this end, we monitored host transcript expression values in a panel of 20 human MM cell lines (HMCLs) and focused on transcripts whose expression varied significantly across the dataset.</p> <p>Methods</p> <p>miRNA expression was quantified by Quantitative Real-Time PCR. Gene expression and genome profiling data were generated on Affymetrix oligonucleotide microarrays. Significant Analysis of Microarrays algorithm was used to investigate differentially expressed transcripts. Conventional statistics were used to test correlations for significance. Public libraries were queried to predict putative miRNA targets.</p> <p>Results</p> <p>We identified transcripts specific to six miRNA host genes (<it>CCPG1</it>, <it>GULP1</it>, <it>EVL</it>, <it>TACSTD1</it>, <it>MEST</it>, and <it>TNIK</it>) whose average changes in expression varied at least 2-fold from the mean of the examined dataset. We evaluated the expression levels of the corresponding intronic miRNAs and identified a significant correlation between the expression levels of <it>MEST</it>, <it>EVL</it>, and <it>GULP1 </it>and those of the corresponding miRNAs miR-335, miR-342-3p, and miR-561, respectively. Genome-wide profiling of the 20 HMCLs indicated that the increased expression of the three host genes and their corresponding intronic miRNAs was not correlated with local copy number variations. Notably, miRNAs and their host genes were overexpressed in a fraction of primary tumors with respect to normal plasma cells; however, this finding was not correlated with known molecular myeloma groups. The predicted putative miRNA targets and the transcriptional profiles associated with the primary tumors suggest that <it>MEST</it>/miR-335 and <it>EVL/</it>miR-342-3p may play a role in plasma cell homing and/or interactions with the bone marrow microenvironment.</p> <p>Conclusion</p> <p>Our data support the idea that intronic miRNAs and their host genes are regulated dependently, and may contribute to the understanding of their biological roles in cancer. To our knowledge, this is the first evidence of deregulated miRNA expression in MM, providing insights that may lead to the identification of new biomarkers and altered molecular pathways of the disease.</p

Circ-ZNF609 Is a Circular RNA that Can Be Translated and Functions in Myogenesis

Circular RNAs (circRNAs) constitute a family of transcripts with unique structures and still largely unknown functions. Their biogenesis, which proceeds via a back-splicing reaction, is fairly well characterized, whereas their role in the modulation of physiologically relevant processes is still unclear. Here we performed expression profiling of circRNAs during in vitro differentiation of murine and human myoblasts, and we identified conserved species regulated in myogenesis and altered in Duchenne muscular dystrophy. A high-content functional genomic screen allowed the study of their functional role in muscle differentiation. One of them, circ-ZNF609, resulted in specifically controlling myoblast proliferation. Circ-ZNF609 contains an open reading frame spanning from the start codon, in common with the linear transcript, and terminating at an in-frame STOP codon, created upon circularization. Circ-ZNF609 is associated with heavy polysomes, and it is translated into a protein in a splicing-dependent and cap-independent manner, providing an example of a protein-coding circRNA in eukaryotes

Inflammatory bowel disease: pathogenesis, diagnosis and current therapeutic approach

Inflammatory bowel disease is a group of conditions of unknown etiology, represented by Crohn’s disease and ulcerative colitis and characterized by the presence of intestinal wall inflammation. From the first cases described to date, several studies have been performed to elucidate the cause of inflammatory bowel disease. Generally, the genetic factors predispose to their occurrence while epigenetic and environmental factors trigger them. Genetic factors are mutations of the genes involved in the response and recognition of immune cells to different pathogens. The most studied epigenetic and environmental factors are smoking (which predisposes to Crohn’s disease and can be protective for ulcerative colitis), lack of vitamin D, a diet rich in sugars and low in flavonoids and fibers. The diagnosis is usually established by endoscopy and biopsy. Recent technologies can perform live biopsies such as endocytoscopy or confocal laser endomicroscopy, with an accuracy of 100% compared to classical methods. Therapy involves several classes of drugs, preferably in association with diet and lifestyle changes. In case of complications or in non-responsive diseases, surgery must be considered, as documented for ulcerative colitis that can be cured by removing the entire colon. The purpose of this review is to present recent findings on pathology, as well as modern diagnosis and treatment methods for IBD

Postoperative complicated appendectomy revealing Crohn’s disease in a pediatric patient

Granulomatous appendicitis is a very rare entity in children. It is related to Crohn’s disease in only 5-10% of the cases. The diagnosis of Crohn’s disease is a real challenge in the pediatric population, especially when its initial manifestation is acute appendicitis. Herein, we present a 13-year-old boy admitted for acute appendicitis. The histopathological examination was conclusive for acute granulomatous appendicitis. The development of an entero-cutaneous fistula has complicated the postoperative evolution. The failure of the conservative management required ileocecal resection. The pathological examination revealed Crohn’s disease. The one-year follow-up on the patient din not reveal any complications. We strongly support the importance of the histopathological examination of the entirely removed appendix. Careful assessment of granulomatous appendicitis is needed in order to establish its possible etiology and to initiate the adequate treatment