Identification of archaeal proteins that affect the exosome function in vitro

Background  

The archaeal exosome is formed by a hexameric RNase PH ring and three RNA binding subunits and has been shown to bind and degrade RNA in vitro. Despite extensive studies on the eukaryotic exosome and on the proteins interacting with this complex, little information is yet available on the identification and function of archaeal exosome regulatory factors.     

Electron paramagnetic resonance of the 4f65d excited state of Eu2+ in KCl single crystals

Optical detection of the Electron Paramagnetic Resonance of the lowest-lying energy level of the 4f⁶5d excitated state of the Eu²⁺ ion in monocrystalline KCl is reported. The values for the hyperfine interaction constants of the two europium isotopes ¹⁵¹Eu and ¹⁵³Eu were found to be 470 and 200 gauss, respectively, these values being considerably larger than those found for the ground state configuration. This increase may be explained in terms of a large change in the core polarization contribution to the effective magnetic field experienced by the europium nucleus. On the other hand, the value obtained for the g-factor (～2.1) points toward an isotropic exchange coupling between the 4f and 5d spin components.     

Magnetic field effects on the fluorescence of Cr3+ in GdAlO3

The fluorescence spectrum of Cr³⁺ in GdAlO₃ has been examined at 4.2 K as a function of magnetic field up to 60 kG. The resulting splitting of the ²E → ⁴A₂ emission lines are explained in terms of a modified molecular field approximation, which incorporates the effect of the spin fluctuations. The exchange constant in the relaxed excited state is found to be 1.2 cm^-1, which differs from that reported from absorption data. It is suggested that the difference may be related to the Frank-Condon effect.     

Modulation of humoral immune response to oral BCG vaccination by Mycobacterium bovis BCG Moreau Rio de Janeiro (RDJ) in healthy adults

We hypothesize that the energy strategy of a cell is a key factor for determining how, or if, the immune system interacts with that cell. Cells have a limited number of metabolic states, in part, depending on the type of fuels the cell consumes. Cellular fuels include glucose (carbohydrates), lipids (fats), and proteins. We propose that the cell's ability to switch to, and efficiently use, fat for fuel confers immune privilege. Additionally, because uncoupling proteins are involved in the fat burning process and reportedly in protection from free radicals, we hypothesize that uncoupling proteins play an important role in immune privilege. Thus, changes in metabolism (caused by oxidative stresses, fuel availability, age, hormones, radiation, or drugs) will dictate and initiate changes in immune recognition and in the nature of the immune response. This has profound implications for controlling the symptoms of autoimmune diseases, for preventing graft rejection, and for targeting tumor cells for destruction.     

Investigation of New Ion-Conducting ORMOLYTES: Structure and Properties

Two families of hybrid organic-inorganic composites exhibiting Li⁺ ionic conduction (ORMOLYTES) have been prepared by the sol-gel process. The first family, prepared from a mixture of 3-isocyanatopropyltriethoxysilane, O,O Bis (2-aminopropyl)-polyethyleneglycol (or O,O Bis (2-aminopropyl)-polypropyleneglycol) and lithium salt, presents chemical bonds between the organic and the inorganic phase and an ionic conductivity higher than 10^-4 S m^-1 at room temperature. Their properties have been related to their structure using liquid state NMR measurements of ⁷Li between -100°C and +100°C and the DMTA technique. In the second family, prepared by ultrasonic method from a mixture of tetraethoxysilane (TEOS), polyethyleneglycol (PEG) and lithium salt, the organic and inorganic phases are not chemically bonded. Ionic conductivity has been studied as a function of the polymer chain length and concentration. Values of up to 10^-2 S m^-1 at room temperature have been obtained (with a silica-PEG₃₀₀ system, PEG/TEOS = 40% in weight). Again, structure was investigated by liquid state ⁷Li NMR measurements.     

Experimental demonstration of guiding and confining light in nanometer-size low-refractive-index material

We experimentally demonstrate a novel silicon waveguide structure for guiding and confining light in nanometer-wide low-refractive-index material. The optical field in the low-index material is enhanced because of the discontinuity of the electric field at high-index-contrast interfaces. We measure a 30% reduction of the effective index of light propagating in the novel structure due to the presence of the nanometer-wide low-index region, evidencing the guiding and confinement of light in the low-index material. We fabricate ring resonators based on the structure and show that the structure can be implemented in highly integrated photonics.     

Subthreshold parallel pumping near and above the critical temperature in K2CuF4 and (CH3NH3)2CuCl4

Parallel pumping absorption below the threshold for spin-wave instability was observed near and above the critical temperature T_c in the quasi-two-dimensional ferromagnets K₂CuF₄ and (CH₃NH₃)₂CuCl₄. The absorption shape is well described by the density of states of the two-dimensional magnons at T?T_c, and gradually changes to a more symmetric peak with increasing temperature well above T_c.     

Trichloro-bridged diruthenium (III,III) complexes: X-ray isomorphous structures of [Ph3X=O···H···O=XPh3][Ru2Cl7(XPh3)2]·0.5(CH2Cl2)(H2O)(X = As or P)

The triply chloro-bridged binuclear complexes [Ph₃X=O···H···O=XPh₃][Ru₂Cl₇(XPh₃)₂]·0.5(CH₂Cl₂)(H₂O) (X = As or P) were obtained from [RuCl₃(XPh₃)₂DMA]·DMA (DMA = dimethylacetamide) CH₂Cl₂/Et₂O solution. The structures were characterized by X-ray diffraction studies. The complexes are formed from two Ru atoms bridged by three chloride anions. The two ruthenium atoms are also coordinated to two non-bridging Cl atoms and an AsPh₃ or PPh₃ ligand respectively. As an interesting feature, the cations of these complexes are protons, trapped in a very short hydrogen bond between two triphenylarsine or triphenylphosphine oxide molecules.