4 research outputs found
Persistence of magnetic field driven by relativistic electrons in a plasma
The onset and evolution of magnetic fields in laboratory and astrophysical
plasmas is determined by several mechanisms, including instabilities, dynamo
effects and ultra-high energy particle flows through gas, plasma and
interstellar-media. These processes are relevant over a wide range of
conditions, from cosmic ray acceleration and gamma ray bursts to nuclear fusion
in stars. The disparate temporal and spatial scales where each operates can be
reconciled by scaling parameters that enable to recreate astrophysical
conditions in the laboratory. Here we unveil a new mechanism by which the flow
of ultra-energetic particles can strongly magnetize the boundary between the
plasma and the non-ionized gas to magnetic fields up to 10-100 Tesla (micro
Tesla in astrophysical conditions). The physics is observed from the first
time-resolved large scale magnetic field measurements obtained in a laser
wakefield accelerator. Particle-in-cell simulations capturing the global plasma
and field dynamics over the full plasma length confirm the experimental
measurements. These results open new paths for the exploration and modelling of
ultra high energy particle driven magnetic field generation in the laboratory
Genome-Wide Gene Expression Analysis Suggests an Important Role of Suppressed Immunity in Pathogenesis of Kashin-Beck Disease
OBJECTIVE: To investigate the differences between the gene expression profiles in peripheral blood mononuclear cells (PBMC) from normal controls and patients with Kashin-Beck disease (KBD). METHODS: Twenty KBD patients and 12 normal subjects were selected from a KBD-endemic area and divided into four pairs of KBD vs. control (KBD, n = 5 per pair; control, n = 3 per pair). RNAs were respectively isolated from KBD PBMCs and normal PBMCs. Gene expression profiles were analyzed by oligonucleotide microarray. The gene expression profiles in PBMCs from KBD patients and normal controls were compared and the differentially expressed genes were identified. The obtained microarray data was further confirmed by using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: Approximately 501 genes, corresponding to 2.4% of the total probe transcripts, showed a 2-fold change in differential expression. 19.4% (97 out of 501)of the differentially expressed genes were commonly detected in all the four pairs. Among the 97 differentially expressed genes, 83 genes were up-regulated and 14 genes were down-regulated, compared with those in the normal controls. Some differentially expressed genes were found to be related to functions such as immunity, metabolism, apoptosis, cystoskeleton and cell movement, and extracellular matrix. The validity of our microarray data were supported by the results of qRT-PCR assay. CONCLUSION: Differences in the PBMC gene expression profile between the KBD patients and the normal controls exhibited a similar pattern among all the four pairs of microarrays examined, indicating that the suppressed immunity may play an important role in the pathogenesis of KBD