Search results

Sort By:

Limit search:

Maturation Process of Photosynthetic Membranes Observed by Proton Magnetic Relaxation and Sorption Isotherm

100%

Harańczyk H., Leja A., Jemioła-Rzemińska M., Strzałka K.

Acta Physica Polonica A

2009

vol. 115

issue 2

526-532

Mild rehydration from the gaseous phase of the developing and mature lyophilized wheat photosynthetic membranes was investigated using hydration kinetics, adsorption isotherm and high power proton relaxometry. Hydration time courses are single exponential for all target air humidities; the hydration time t^h equals to (11.9±3.6) h for the mature membranes, and (17.0±3.2) h for the developing membranes. The sorption isotherm is sigmoidal in form and well fitted using the Dent model; the mass of water saturating primary binding sites equals Δ M/m_0= 0.033±0.013 and 0.025±0.007 for the mature and for the developing membranes, respectively, where m_0 is the dry mass of the sample, and Δ M is mass of water taken up. Proton free induction decays distinguish: (i) an immobilized proton (Gaussian) component, S_0, originating from protons of solid matrix of lyophilizate; (ii) a Gaussian component, S_1, from water bound to the primary water binding sites and localized in proximity of paramagnetic ions; (iii) an exponentially decaying contribution, L_1, from water tightly bound to lyophilizate surface; and (iv) exponentially decaying loosely bound water pool, L_2. A significant contribution of water "sealed" in the structure of lyophilized membrane (from the fraction S_1 and L_1) is detected. The mass of "sealed" water fraction is Δ M_{S}/m_0 = 0.047±0.023 and 0.072±0.021 for the mature and for the developing membranes, respectively.

Rehydration of Digalactosyldiacylglycerol Model Membrane Lyophilizates Observed by NMR and Sorption Isotherm

88%

Harańczyk H., Bacior M., Jamróz J., Jemioła-Rzemińska M., Strzałka K.

Acta Physica Polonica A

2009

vol. 115

issue 2

521-525

The initial stages of rehydration of digalactosyldiacylglycerol model membrane lyophilizates were observed using hydration kinetics, sorption isotherm, and high power proton relaxometry (at 30 MHz). Hydration time courses are single exponential and the sorption isotherm is sigmoidal in form. The mass of water saturating primary binding sites equals Δ M/m_0= 0.019±0.001. Proton free induction decays distinguish (i) immobilized protons of solid matrix of lyophilizate, signal S_0; (ii) protons of water fraction tightly bound to the lyophilizate surface, L_1; and (iii) mobile protons of loosely bound water pool, L_2. Hydration dependence of total water signal (L_1+L_2)/S_0 shows the presence of water fraction "sealed" in liposome structures, which equals Δ M_{S}/m_0 = 0.092±0.007.

Refine search results

2 Acta Physica Polonica A

2 2009

2 Harańczyk H.

2 Jemioła-Rzemińska M.

2 Strzałka K.

1 Bacior M.

1 Jamróz J.

1 Leja A.

Search results

Maturation Process of Photosynthetic Membranes Observed by Proton Magnetic Relaxation and Sorption Isotherm

Rehydration of Digalactosyldiacylglycerol Model Membrane Lyophilizates Observed by NMR and Sorption Isotherm