Scattering, injection and acceleration of field aligned beam ions at quasi-parallel shock: a hybrid simulation study

The process of injection into the first-order Fermi acceleration, also called diffusive shock acceleration or DSA, at quasi-parallel shocks is still not completely understood. In our analysis, we study the scattering and the acceleration of field aligned beam ions in the foreshock region of a quasi-parallel shock by using a 1D hybrid simulation setup. Test particles are introduced into the simulation box in a developed foreshock wave field and these particles are followed until the end of the experiment. Our results show that more than 40% of the original FAB ions reach the shock and become accelerated to energies that are typical of diffuse ions. Keywords: collisionless plasma, diffusive shock acceleration, ion injectio

Sap-specifikus fehérjekölcsönhatások azonosítása és szerepük a T-limfocita funkciókban = Identification of sap-specific protein interactions in T-cells and their role in T-cell function

A pályázat fő célkitűzése a SLAM (signaling limfocilymphocyte activation molecule) koreceptor molekula immunregulációs szerepének vizsgálata volt. A SAP (SLAM associated protein ) és az EAT-2 (Ewing Sarcoma Associated Transcript-2) szerepe a SLAM család receptorainak szignalizációs folyamataiban bizonyított. Kimutattuk, hogy a SAP és az EAT-2 molekula a Fyn molekulán kívül a Hck, az Lck a Lyn, és az Fgr kinázzal is képes kapcsolódni. Ezen interakciók nem az SH3, hanem a kináz domén kapcsolódásával jönnek létre. A src-családba tartozó kinázok aktivitásának szabályozása a kináz doménnel történő interakción keresztül eddig ismeretlen, így az általunk felfedezett interakciók egy új szabályozó mechanizmus megismeréséhez vezethetnek. Az aktivált dendritikus sejtek és T-sejtek felszínén expresszálódó SLAM receptor indukálta szignalizációs folyamatok modellezésére in vitro kísérleti rendszert állítottunk be és vizsgáltuk a SLAM szignalizáció CD40L- és/vagy LPS-aktivációra gyakorolt hatását dendritikus sejtekben. Kimutattuk, hogy a SLAM receptor homo-asszociációja általi szignalizáció gátolja dendritikus sejtek CD40ligandum-indukálta gyulladási citokin termelését. (IL-12, TNF-?, IL-6) és csökkenti a naív T-sejtek Th1 irányba történő differenciációját. Valószínűsíthető, hogy DS-T-sejt interakció során létrejövő SLAM homoasszociáció szerepet játszhat a autoimmun eredetű gyulladási folyamatok kialakulásának gátlásában vagy azok intenzitásának csökkentésében. | SLAM (Signaling Lymphocyte Activation Molecule, CD150) is a self-ligand receptor on the surface of activated T- and B-lymphocytes, macrophages and dendritic cells (DCs). Here we have examined the effect of SLAM signaling on dendritic cell functions. The single SH2-domain adaptors SAP (SLAM associated protein ) and EAT-2 (Ewing Sarcoma Associated Transcript-2) are major regulators of SLAM signaling. We found that SAP and EAT-2 interact with Src kinases including Hck, Lck, Lyn, and Fgr both in yeast and in transfected cell lines. Surprisingly, these interactions occur via the kinase domain rather than the SH3-domain of the kinase. The interaction of these adaptors with the kinase domain of Src kinases indicates that a novel pathway may exist to modulate the activity of Src-kinases. To examine the effect of SLAM signaling on CD40L and/or LPS induced dendritic cell functions we developed an in vitro model system. We found that SLAM-signaling strongly inhibited CD40L-induced production of IL-12, IL-6, TNF-?. LPS-induced IL-12 secretion, however, was not inhibited, rather increased by SLAM-engagement. Finally, CD40L-activated DCs affected by exposure to SLAM/SLAM engagement were impaired in their ability to induce differentiation of na?ve T lymphocytes into IFN-? producing Th1 effector cells. These findings implicate SLAM as a potent regulator of physiological or pathological inflammatory responses that may have an impact on the clinical management of autoimmune diseases

A geomágneses viharok anatómiája és következményeik

A tanulmány részletesen bemutatja a geomágneses vihar keletkezési folyamatát és fő fázisait. A szerző ismerteti a skálázási lehetőséget – amely az „enyhe” (G1) fokozattól a „rendkívüli” (G5) fokozatig terjed –, illetve a geomágneses vihar lehetséges következményeit. Vizsgálja a geomágneses vihar esetén kialakuló kéregáramok keletkezési mechanizmusát, és a jelenség által okozott veszélyeket. Végül áttekintést ad néhány történelmi jelentőségű geomágneses viharról, és bemutatja az azok kapcsán megfigyelt jelenségeket

Chlamydia pneumoniae in atherosclerotic middle cerebral artery

Background and Purpose—Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. Methods—Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. Results—Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. Conclusions—The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases

Effect of Upstream ULF Waves on the Energetic Ion Diffusion at the Earthʼs Foreshock. I. Theory and Simulation

Field-aligned diffusion of energetic ions in the Earth’s foreshock is investigated by using the quasi-linear theory (QLT)and test particle simulation

Dehydroepiandrosterone sulfate (DHEAS) is neuroprotective when administered either before or after injury in a focal cortical cold lesion model

Dehydroepiandrosterone and its sulfate (DHEAS) are sex hormone precursors that exert marked neurotrophic and/or neuroprotective activity in the central nervous system. The present study evaluated the effects of DHEAS and 17�-estradiol (E2) in a focal cortical cold lesion model, in which DHEAS (50 mg/kg, sc) and E2 (35 mg/kg, sc) were administered either as pretreatment (two subsequent injections 1 d and 1 h before lesion induction) or posttreatment (immediately after lesion induction). The focal cortical cold lesion was induced in the primary motor cortex by means of a cooled copper cylinder placed directly onto the cortical surface. One hour later, the animals were killed, the brains cut into 0.4-mm-thick slices, and the sections stained with 1% triphenyltetrazolium chloride. The volume of the hemispheric lesion was calculated for each animal. The results demonstrated that the lesion area was significantly attenuated in both the DHEAS- and E2- preand posttreated groups and that in the presence of letrozole, a nonsteroidal aromatase inhibitor, no neuroprotection was observed, suggesting that the beneficial effect of DHEAS on the cold injury might depend on the conversion of DHEAS to E2 within the brain. It is concluded that even a single posttraumatic administration of DHEAS may be of substantial therapeutic benefit in the treatment of focal brain injury with vasogenic edema