BACKGROUND Cathepsin K (CatK), a cysteine protease with the potent elastolytic activity, plays a predominant role in intracellular elastin degradation in human dermal fibroblasts (HDFs), and contributes to solar elastosis. In previous studies, CatK expression was downregulated in photoaged skin and fibroblasts, but upregulated in acute UVA-irradiated skin and fibroblasts. The underlying mechani...

DNA-damage-induced apoptosis and cellular senescence are perceived as two distinct cell fates. We found that after ionizing radiation (IR)-induced DNA damage the majority (up to 70 %) of senescent human diploid fibroblasts (HDFs) were subjected to controlled cleavage of DNA, resulting in the establishment of a viable and stable sub-G1 population, i.e. deeply senescent cells. We show that in sen...

Hadoop, an open source java framework deals with big data. It has HDFS (Hadoop distributed file system) and MapReduce. HDFS is designed to handle large amount files through clusters and suffers performance penalty while dealing with large number of small files. These large numbers of small files pose a heavy burden on the NameNode of HDFS and an increase execution time for MapReduce. Secondly, ...

Yellow elephants are slow. A major reason is that they consume their inputs entirely before responding to an elephant rider’s orders. Some clever riders have trained their yellow elephants to only consume parts of the inputs before responding. However, the teaching time to make an elephant do that is high. So high that the teaching lessons often do not pay off. We take a different approach. We ...

In this report we describe how we adapted the Parallel Log Structured Filesystem (PLFS) to enable HPC applications to be able read and write data from the HDFS cloud storage subsystem. Our enhanced version of PLFS provides HPC applications with the ability to concurrently write from multiple compute nodes into a single file stored in HDFS, thus allowing HPC applications to checkpoint. Our resul...

[email protected] THE HADOOP D I S TR I BUTED F I L E System (HDFS) has a single metadata server that sets a hard limit on its maximum size. Ceph, a high-performance distributed file system under development since 2005 and now supported in Linux, bypasses the scaling limits of HDFS. We describe Ceph and its elements and provide instructions for installing a demonstration system that can be used...

Many open source projects are lacking architectural documentation that describes the major pieces of the system, how they are structured, and how they interact. We have produced architectural documentation for the Hadoop Distributed File System (HDFS), a major open source project. This paper describes our process and experiences in developing this documentation. We illustrate the documentation ...

BACKGROUND The mechanism by which human cytomegalovirus (HCMV) stimulates oncogenesis is unclear. Because cellular immortalization and transformation require telomerase activation by expression of the telomerase reverse transcriptase (hTERT) gene, we examined the role of HCMV in telomerase activation. METHODS Normal human diploid fibroblasts (HDFs) and human malignant glioma (MG) cell lines w...

The Quantcast File System (QFS) is an efficient alternative to the Hadoop Distributed File System (HDFS). QFS is written in C++, is plugin compatible with Hadoop MapReduce, and offers several efficiency improvements relative to HDFS: 50% disk space savings through erasure coding instead of replication, a resulting doubling of write throughput, a faster name node, support for faster sorting and ...