Characterization of mercury(II)-induced inhibition of photochemistry in the reaction center of photosynthetic bacteria

Mercuric contamination of aqueous cultures results in impairment of viability of photosynthetic bacteria primarily by inhibition of the photochemistry of the reaction center (RC) protein. Isolated reaction centers (RCs) from Rhodobacter sphaeroides were exposed to Hg(2+) ions up to saturation concentration (~ 10(3) [Hg(2+)]/[RC]) and the gradual time- and concentration-dependent loss of the photochemical activity was monitored. The vast majority of Hg(2+) ions (about 500 [Hg(2+)]/[RC]) had low affinity for the RC [binding constant Kb ~ 5 mM(-1)] and only a few (~ 1 [Hg(2+)]/[RC]) exhibited strong binding (Kb ~ 50 muM(-1)). Neither type of binding site had specific and harmful effects on the photochemistry of the RC. The primary charge separation was preserved even at saturation mercury(II) concentration, but essential further steps of stabilization and utilization were blocked already in the 5 < [Hg(2+)]/[RC] < 50 range whose locations were revealed. (1) The proton gate at the cytoplasmic site had the highest affinity for Hg(2+) binding (Kb ~ 0.2 muM(-1)) and blocked the proton uptake. (2) Reduced affinity (Kb ~ 0.05 muM(-1)) was measured for the mercury(II)-binding site close to the secondary quinone that resulted in inhibition of the interquinone electron transfer. (3) A similar affinity was observed close to the bacteriochlorophyll dimer causing slight energetic changes as evidenced by a ~ 30 nm blue shift of the red absorption band, a 47 meV increase in the redox midpoint potential, and a ~ 20 meV drop in free energy gap of the primary charge pair. The primary quinone was not perturbed upon mercury(II) treatment. Although the Hg(2+) ions attack the RC in large number, the exertion of the harmful effect on photochemistry is not through mass action but rather a couple of well-defined targets. Bound to these sites, the Hg(2+) ions can destroy H-bond structures, inhibit protein dynamics, block conformational gating mechanisms, and modify electrostatic profiles essential for electron and proton transfer

The Sorption Behavior of Cs+ ion On Clay Minerals and Zeolite in Radioactive Waste Managemen: Sorption Kinetics and Themodynamics

Cataloged from PDF version of article.In this work, Cs+ ion sorption on some clays and zeolite were investigated. Cs-137 was used as a tracer. Activities were measured with a NaI crystal gamma counter. The particle size distribution was determined by a laser sizer. Surface area of the particles were determined by BET (Brunauer, Emmett and Teller method). Structure analysis was made by using X-ray diffraction. The chemical compositions of the solid samples were determined using a ICAP-OE spectrometer. Kinetic and thermodynamic parameters were determined. Due to very high uptake results; clay and zeolite can be proposed as a good sorbents in waste management considerations

Nemzetközi büntetőjog és nemzetközi büntető igazságszolgáltatás = International criminal law and international criminal justice

A projekt megvalósítása során a magyar szakirodalomban elsőként végeztünk kutatásokat az un. nemzetközi jogi bűncselekmények (háborús- és emberiesség elleni bűncselekmények, a kínzás, illetve a népirtás) jogtörténeti és dogmatikája körében, illetve a nemzetközi büntetőbíróságok vonatkozó judikatúrájának bemutatására. A kutatás során a hangsúlyt a nemzetközi büntetőjogi felelősség speciális formáinak - az elöljáró (parancsnok) speciális felelőssége, joint criminal enterprise, az állam büntetőjogi felelőssége - feldolgozására helyeztük, illetve elemzésre kerültek a nemzetközi büntetőjogban és a nemzetközi jogban szabályozott büntethetőségi akadályok. Végül vizsgálat tárgyát képezte a nemzetközi büntetőbíráskodás kérdésköre, figyelemmel elsősorban a jogtörténeti előzményekre, illetve az ad hoc nemzetközi törvényszékek, illetve a Nemzetközi Büntetőbíróság működésére, az ezek előtt folyó bizonyításra. Ezen túlmenően kutatások kiterjedtek az EU büntetőjogi együttműködési rendszerére a jövőbeni fejlődési irányaira. Ezen a területen belül a magyar kutatások között elsőként foglalkoztunk a terrorizmus és a titkos információszerzés európai dimenzióinak jogi aspektusaival. | In this OTKA project we made first in Hungary research work on both historical and doctrinal aspects as well as court practice analysis of international crimes (war crimes, crimes against humanity, torture and genocide). In our research work we put the emphasis on the special forms of international criminal responsility (criminal responsibility of commanding officer, of joint criminal enterprises and of state). We analysed the problems of justification and excuse in international law and international criminal law as well. We also examined the historical aspects of the main issues of international criminal jurusdiction, the role of, and the rules of evidence before the ad hoc international criminal tribunals and International Criminal Court. Beyond these issues the project focused first in Hungary on the evolution and the future perspectivesof the criminal law cooperation system of the EU with special referece to the legal problems of terrorism and covert operations

Microstructures in Two Alkali Feldspar Megacrysts from the Papuk Mt., Croatia

Two types of megacrysts, one from Pakra Creek and the other from the Slobostina Creek locality proved to be low microcline in association with low albite and quartz. A sample from Pakra Creek is a vein filling megacryst characterised by the absence of twinning. The deduced crystallization temperature is below 460°C. The sample from Sloboština Creek is a pocket forming megacryst which shows tweed-like texture, with deduced crystallization temperature near to but above 460°C. Both samples are characterized by a continuously modulated lattice on the submicroscopic scale