The pulsed electron paramagnetic resonance (EPR) methods of electron spin echo envelope modulation (ESEEM) and electron spin echo-electron nuclear double resonance (ESE-ENDOR) are used to investigate the structure of the Photosystem II oxygen-evolving complex (OEC), including the paramagnetic manganese cluster and its immediate surroundings. Recent unpublished results from the pulsed EPR labora...

The capabilities and limitations of the Becke-3-Lee-Yang-Parr (B3LYP) density functional theory (DFT) for modeling proton coupled electron transfer (PCET) in the mixed-valence oxomanganese complex 1 [(bpy)(2)Mn(III)(mu-O)(2)Mn(IV)(bpy)(2)](3+) (bpy = 2,2'-bipyridyl) are analyzed. Complex 1 serves as a prototypical synthetic model for studies of redox processes analogous to those responsible for...

The hydration of the oxygen-evolving complex (OEC) was characterized in the dark stable S1 state of photosystem II using water R1(ω) NMR dispersion (NMRD) profiles. The R1(ω) NMRD profiles were recorded over a frequency range from 0.01 MHz to 40 MHz for both intact and Mn-depleted photosystem II core complexes from Thermosynechococcus vulcanus (T. vulcanus). The intact-minus-(Mn)-depleted diffe...

Epiphytic filamentous algae (EFA) were noted as a serious problem to reduce the production and quality of K. alvarezii. The morphological studies revealed that the main epiphyte on K. alvarezii was Neosiphonia savatieri in China. Though the harmful effects of EFA on the production of K. alvarezii have been reported, the detailed mechanism of the N. savatieri in limiting the production of K. alv...

Addition of non-saturating amounts of 2,3-DPG (2,3-diphosphoglycerate) within the red cell (2,3-DPG/haemoglobin less than 1) initially reduces Hill's parameter, n. With increasing 2,3-DPG/haemoglobin, n increases until a maximum is reached at 2,3-DPG/haemoglobin greater than 1. Thus, 2-3-DPG influences the shape as well as the position of the whole blood oxygen equilibrium curve (OEC). The impo...

The objective of the present study was to experimentally investigate and compare characteristics three oxygen-enhanced combustion (OEC) methods; premix enrichment (PE), air-oxy/fuel (AO), additionally also oxygen lancing (OL) method. overall concentration varied from 21% 38%. Combustion tests were carried out using gas burner with thermal input 750 kW fired by natural gas. OEC methods, such as ...

Nearly all of the dioxygen which animals and aerobic bacteria use during respiration originates from the photosynthetic oxygen evolving complex (OEC) which is found in the chloroplast thylakoid membranes of higher plants and algae. Four specifically bound Mn are required for OEC activity [l]. These manganese do not exhibit the six line epr spectrum which is characteristic of Mn(IIj in solution,...

background: the failure of regeneration after spinal cord injury (sci) has been attributed to axonal demyelination and neuronal death. cellular replacement and white matter regeneration are both necessary for sci repair. in this study, we evaluated the co-transplantation of olfactory ensheathing cells (oec) and embryonic stem (es) cell-derived motor neurons (esmn) on contused sci. methods: oec ...

Background: The failure of regeneration after spinal cord injury (SCI) has been attributed to axonal demyelination and neuronal death. Cellular replacement and white matter regeneration are both necessary for SCI repair. In this study, we evaluated the co-transplantation of olfactory ensheathing cells (OEC) and embryonic stem (ES) cell-derived motor neurons (ESMN) on contused SCI. Methods: OEC...

Photosystem II (PSII) uses light energy to split water into protons, electrons and O2. In this reaction, nature has solved the difficult chemical problem of efficient four-electron oxidation of water to yield O2 without significant amounts of reactive intermediate species such as superoxide, hydrogen peroxide and hydroxyl radicals. In order to use nature's solution for the design of artificial ...