Galaxy clusters enveloped by vast volumes of relativistic electrons.

The central regions of galaxy clusters are permeated by magnetic fields and filled with relativistic electrons1. When clusters merge, the magnetic fields are amplified and relativistic electrons are re-accelerated by turbulence in the intracluster medium2,3. These electrons reach energies of 1-10 GeV and, in the presence of magnetic fields, produce diffuse radio halos4 that typically cover an area of around 1 Mpc2. Here we report observations of four clusters whose radio halos are embedded in much more extended, diffuse radio emission, filling a volume 30 times larger than that of radio halos. The emissivity in these larger features is about 20 times lower than the emissivity in radio halos. We conclude that relativistic electrons and magnetic fields extend far beyond radio halos, and that the physical conditions in the outer regions of the clusters are quite different from those in the radio halos.

A radio ridge connecting two galaxy clusters in a filament of the cosmic web.

Galaxy clusters are the most massive gravitationally bound structures in the Universe. They grow by accreting smaller structures in a merging process that produces shocks and turbulence in the intracluster gas. We observed a ridge of radio emission connecting the merging galaxy clusters Abell 0399 and Abell 0401 with the Low-Frequency Array (LOFAR) telescope network at 140 megahertz. This emission requires a population of relativistic electrons and a magnetic field located in a filament between the two galaxy clusters. We performed simulations to show that a volume-filling distribution of weak shocks may reaccelerate a preexisting population of relativistic particles, producing emission at radio wavelengths that illuminates the magnetic ridge.

BIOCOMPATIBLE TARGETING HYDROGELS FOR BREAST CANCER TREATMENT.

Hydrogels have received growing attention as materials for drug delivery systems (DDS) because of their biodegradable and biocompatible properties. DDS were developed to optimize the therapeutic properties of drug products and to render them more safe, effective, and reliable. In the past, drugs were frequently administered orally, as liquids or in powder forms. To avoid problems incurred through the utilization of the oral route of administration, new dosage forms, DDS, containing the drugs were introduced. They can deliver drugs directly to the intended site of action and can also improve treatment efficacy, while minimizing unwanted side effects elsewhere in the body, which often limit the long-term use of many drugs, and provide better efficacy of treatment. Biocompatible hydrogels are an example of such systems available for therapeutic use. In this review, results from recent publications concerning these systems are discussed. Hydrogels show superior effectiveness over conventional methods of treatment providing controlled release of active substances. They are of interest in medical applications such as breast cancer treatment.

Spherical molecularly imprinted polymers (SMIPs) via a novel precipitation polymerization in the controlled delivery of sulfasalazine.

Spherical molecularly imprinted polymers (SMIPs) have been prepared via a novel precipitation polymerization using sulfasalazine (prodrug used in the diseases of the colon) as template. The sulfasalazine was incorporated into SMIPs and into a spherical non-imprinted polymer (control), and then the release rate of the bioactive agent at different pH values was evaluated. Considerable differences in the release characteristics between imprinted and non-imprinted polymers have been observed. This opens the possibility of the development of drug release systems capable of modulating the release of a specific molecule. Photomicrography of spherical molecularly imprinted polymers (SMIPs).