A detection of-rays from Mkn 421 at energies above 1 TeV is reported, based on observations made in December 1994-May 1995 with the rst two HEGRA Cherenkov telescopes. From the image analysis, 111 excess gamma candidates are obtained from the 26 h Telescope #1 (CT1) dataset (signiicance 4.0) and 218 from the 41 h Telescope #2 (CT2) dataset (signiicance 4.2) at zenith angles < 25. The combined s...

miRNAs as one of the potential therapeutic agents have been recently considered for cancer treatment. AS1411 (aptNCL) is a DNA aptamer specifically binding to nucleolin protein on the cancer cell surface with antiproliferative effect. The aim of the study was to develop a conjugate consisted of aptNCL (as targeted delivery of therapeutic agent) and miRNA let-7d (as a tumor suppressor) using two...

Results obtained with BeppoSAX observations of blazars within various collaborative programs are presented. The spectral similarity “paradigm”, whereby the spectral energy distributions of blazars follow a sequence, leading to a unified view of the whole population, is briefly illustrated. We concentrate on recent observations of flares and associated spectral variability long for three objects...

The recent detection of gamma radiation from Mkn 501 at energies as high as ∼ 25 TeV suggests stringent upper bounds on the diffuse, far infrared, extragalactic radiation density. The production of electron-positron pairs through photon-photon collisions would prevent gamma photons of substantially higher energies from reaching us across distances of order 100Mpc. However, coherently arriving T...

We present a new method to reconstruct the arrival direction of individual air showers. The method is based in part on the arrival direction reconstruction method of Lessard et al. [1] from the Whipple collaboration, but yields a significant 30% improvement in the obtained angular resolution. The method was successfully tested on Monte Carlo Simulations and real data of Mkn 421, Mkn 501 and 1ES...

We present results of narrow-band and broad-band optical CCD imaging together with intermediate-resolution spectroscopy of the Wolf-Rayet galaxy Mkn 8. Analysis of the morphology and kinematics of the object indicates that the strong star formation episode we are witnessing in Mkn 8 is the product of the interaction of two (or three) disk galaxies. The chemical abundances and abundance ratios m...

The BL Lac Object Mkn 501 was in a state of high activity in the TeV range in 1997. During this time Mkn 501 was observed by all Cherenkov-Telescopes of the HEGRA-Collaboration. Part of the data were also taken during moonshine thus providing a nearly continuous coverage for this object in the TeV-range. We have carried out a QPO analysis and found evidence for a 23 day periodicity. We applied ...

The extremely rapid burst of TeV photons from Mkn 421 (15 May 1996) can be reconciled with the standard properties of a relativistic γ-ray emitting jet (bulk Lorentz factor Γ ∼ 10; size ∼ 10 cm) if one assumes that the electrons are accelerated in conical shocks with both opening and viewing angles ≈ 1/Γ. If the injection time and the cooling time are much less than the photon crossing time, an...