Pressure-induced hemolysis of in vivo aged human erythrocytes is enhanced by inhibition of water transport via aquaporin-1

Human erythrocytes are fractionated into young, intermediate, and old cells according to their densities. Pressure-induced hemolysis reflects sensitively membrane perturbations. Therefore, the hemolysis of erythrocytes at 200 MPa was examined using fractionated cells. Pressure-induced hemolysis of old (or in vivo aged) erythrocytes was enhanced, compared with those of young and intermediate cells which showed the same hemolytic values. Flow cytometric analysis showed less fragmentation of old erythrocytes under pressure. Moreover, the water transport through the membrane was suppressed in old erythrocytes than intermediate ones. The low permeability of water in old erythrocytes was confirmed by osmotic hemolysis using a hypotonic buffer. These results suggest that water transport via aquaporin-1 (AQP1) is inhibited in old erythrocytes. As the number of AQP1 molecules remained constant in old erythrocytes, the function of AQP1 may be reduced.     

Study of diffusion in erythrocyte suspension using internal magnetic field inhomogeneity

Transport of water and ions through cell membranes plays an important role in cell metabolism. We demonstrate a novel technique to measure water transport dynamics using erythrocyte suspensions as an example. This technique takes advantage of inhomogeneous internal magnetic field created by the magnetic susceptibility contrast between the erythrocytes and plasma. The decay of longitudinal magnetization due to diffusion in this internal field reveals multi-exponential behavior, with one component corresponding to the diffusive exchange of water across erythrocyte membrane. The membrane permeability is obtained from the exchange time constant and is in good agreement with the literature values. As compared to the other methods, this technique does not require strong gradients of magnetic field or contrast agents and, potentially, can be applied in vivo.     

The long-range correlations of various Ising lattices

The object of this paper is to determine the long-range order parameter for any Ising lattice whose partition function can be evaluated by existing methods. The partition function of a general class of two-dimensional lattices is evaluated by a technique found byGreek andHurst, and this technique is extended to determine correlation coefficients. In this way the determination of the long-range correlation coefficients is reduced to an eigenvalue problem, which can be solved by algebraic methods. A simple formula is found for the long-range order parameter, which contains, but is considerably more general than the known result for the rectangular lattice.     

Spin-label study of the microtubule modifier effect on the aqueous-medium microviscosity of nonhardened and cold-hardened winter wheat seedlings

The influence of the substances modifying the microtubule structure, colchicine and dimethyl sulfoxide (DMSO), on the aqueous-medium microviscosity of nonhardened and cold-hardened winter wheat seedlings has been studied with a spin label (1-oxyl-2,2,6,6-tetramethyl-4-oxypiperidine). The correlation times τ_c of rotational diffusion of the labels were found with values for the cold-hardened plants lower than those for the plants grown in optimal temperature conditions. In case of nonhardened tissues colchicine gives the slight increase and DMSO causes the slight decrease of τ_c values in comparison with data for control variant without any treatment. It was explained by opposite changes in plasma membrane permeability and/or hydration or dehydration of cytoskeleton under the treatments. However, these substances do not influence the aqueous medium microviscosity of cold-hardened seedlings. This fact indicates the essential change of the tubulin proteins under cold exposure.     

Study of optical and nanostructural metal-induced changes in erythrocyte membranes by scattering and atomic force microscopy

The surface topography of erythrocyte membranes is studied by atomic force microscopy. Differences in fine structure of membranes are found. The structure of profiles of erythrocyte membranes modified by metals is smoother compared to unmodified erythrocytes. The autocorrelation function of irregularity pro-files of erythrocyte membranes and its parameter (the correlation length) are informative parameters of the action of toxic metals on the erythrocyte membrane surface. The content of metal in an erythrocyte membrane is determined from optical investigations of a suspension of membranes subjected to the action of lead and zinc ions. It is revealed that the luminescence of erythrocyte membranes is enhanced compared to reference data. The absorption spectra of erythrocyte membranes in the range 325–740 nm are calculated from the diffuse transmission and reflection coefficients of samples taking into account their luminescence. The possibility of determining the content of metals in erythrocyte membranes from optical measurements is demonstrated.     

Substance recognition in the open atmosphere from a single Fourier transform spectroradiometer interferogram

An in-situ technique for identification of substances in the open atmosphere from the analysis of a single Fourier-transform spectroradiometer interferogram is described. A database of spectra of major atmospheric constituents and typical atmospheric paths is compiled to be used for the calculation of an atmospheric path with the following separation of a pollutant spectrum from the experimentally recorded spectrum. The identification of a substance by its spectrum is performed through sorting out substances from the database by the correlation coefficients and a quantitative analysis is performed by minimizing the discrepancy functional between the experimental and database spectra. The technique described is tested in situ.     

Membrane deformation of unfixed erythrocytes in air with time lapse investigated by tapping mode atomic force microscopy

Estimation of the time of death is one of the most important problems for forensic medicine and law. Physical and chemical postmortem changes are evaluated together while estimating the time of death. The pattern analysis of antemortem and postmortem bloodstains is one of the important parameters for forensic science, and cellular changes of blood cells can be useful for the quantitative assessment of the time of death. In this study, by successively investigating erythrocytes exposed in air on mica for 5 days using tapping mode atomic force microscopy (TM-AFM), we observed deformation of whole cell and membrane surface of unfixed erythrocytes with time lapse. We found that the time-dependent cellular changes occurred after exposure of erythrocytes in air for several days. At 0.5 days of exposure, fissures and cell shrinkage were observed. At 2.5 days of exposure, the emergence of nanometer-scale protuberances were observed and these protuberances increased in number with increasing time. The changes of cell shape and cell membrane surface ultrastructure can be used to estimate the time of death. Futhermore, smear-induced abnormal erythrocytes and immunostained erythrocytes were observed here. The need for more precise research is indicated, such as the correlation of membrane changes to intervals of less than 0.5 day of air exposure, and use of various substrates in addition to mica, including glass, metals, fabrics, among others, on which the bloodstains appear in crime scenes. The results of this research demonstrate the efficacy of AFM as a potentially powerful analytical tool in forensic science.     

Light scattering by erythrocytes under conditions of osmotic imbalance in a cell-surrounding medium system

A model for changes in the sizes of erythrocytes under conditions of osmotic imbalance in a hypoosmotic medium is proposed assuming free diffusion of water through the erythrocyte membrane. Equations relating the minimum and maximum osmotic resistances to the shape of an erythrocyte in an isotonic medium are obtained. A numerical simulation is used to determine how the optical attenuation coefficient varies as a result of the swelling and hemolysis of erythrocytes; this provides a foundation for a new optical method for determining the osmotic resistance of erythrocytes. This method does not require exerting a force on the erythrocytes, is distinguished by simplicity and high speed, and can be implemented using standard spectrophotometers.     

Hydrogen permeability through sandwich membranes

The problem of hydrogen permeability through sandwich membranes and membranes with nonhomogeneous (by depth) properties as the limiting case of permeability through a sandwich membrane when the thickness of the layers tends to zero is considered. The equation of permeability through sandwich membranes and nonhomogeneous membranes in the steady-state regime is obtained. Analytical dependencies of the permeability reduction factor in four limiting cases are found.     

Analysis of the informativeness of polarization and nephelometric measurements in diagnostics of the microphysical parameters of erythrocytes

Regression relations are found between the microphysical parameters (MPPs) of human blood erythrocytes and the angular coefficients of linear polarization P(??), as well as between the MPPs of erythrocytes and angular coefficients of linear polarization P(??) together with the directional scattering coefficients ??(??). The efficiency of using these regression relations for determining the MPPs of erythrocytes is estimated. It is shown that the involvement of polarization measurements allows one to reduce the error in the retrieval of MPPs, as well as of the size and volume distribution functions, to ??3%.     

Partition functions on the Euclidean plane with compact boundaries in conformal and non-conformal theories

In this paper we calculate the exact partition function for free bosons on the plane with lacunae. First the partition function for a plane with two spherical holes is calculated by matching exactly for the infinite set of Wilson coefficients in an effective world line theory and then performing the ensuing Gaussian integration. The partition is then re-calculated using conformal field theory techniques, and the equality of the two results is made manifest. It is then demonstrated that there is an exact correspondence between the Wilson coefficients (susceptibilities) in the effective field theory and the weights of the individual excitations of the closed string coherent state on the boundary. We calculate the partition function for the case of three holes where CFT techniques necessitate a closed form for the map from the corresponding closed string pants diagrams. Finally, it is shown that the Wilson coefficients for the case of quartic and higher order kernels, where standard CFT techniques are no longer applicable, can also be completely determined. These techniques can also be applied to the case of non-trivial central charges.     

Ultrasound-membrane hybrid processes for enhancement of filtration properties

Enhancing permeation in microfiltration (MF) hollow fiber membrane process was studied under ultrasound (US) by means of reflection technique. The US effect on the enhanced membrane process depended on the position of membrane module with or without a semi-cylindrical shaped reflection plate placed behind the membrane module. Evidence was presented that the membrane process influenced the detected sonic pressure distribution in the US bath. The correlation of sound pressure intensity and luminol fluorescence intensity suggested that violent collapse of cavity bubbles supported the enhanced membrane permeability of MF module in the US bath.     

Effect of a Hydrogen-Bonding Layer on a Hollow Capsule's Permeability

Hollow capsules formed by layer-by-layer self-assembly polymers have been intensively studied for their potential applications in medicine and biotechnology. We have controlled such capsules’ permeability with a hydrogen-bonding layer. Scanning electron microscopy and Fourier transform infrared results showed the fabrication of multilayer polyelectrolyte films. Z-potential results were employed to record the deposition of the polyelectrolyte. The diffusion coefficients for 6-carboxyfluorescein (6-CF) and fluorescently labeled goat anti-human IgG-FITC molecules passing through the wall were calculated based on the fluorescence recovery after photobleaching experiment. The results show that 6-CF molecules can pass through the capsule wall more easily than IgG-FITC molecules. By decreasing the solution's pH, the capsule's permeability to macromolecular dyes or small molecular dyes can be controlled, i.e., the capsule's permeability can be tuned by the hydrogen-bonding interaction.     

Hydrogen isotope permeability of membranes with inhomogeneous properties along the thickness of material

The problem of hydrogen permeation through membranes with inhomogeneous properties along the thickness has been considered as the limiting case of permeation through a multilayered membrane when the layer thicknesses tend to zero. The steady-state permeability equation for multilayer membranes and membranes with inhomogeneous properties along the thickness has been derived. The diffusion equation for the case of inhomogeneous solubility in a membrane has been obtained.     

地层渗透参数反演计算

利用渗流源网格压力(及井底压力)对网格渗透率导数关系(称为渗透率压力场敏感系数)实现由三维渗流方程压强数值解计算井底压力对网格渗透参数导数的计算.基于渗透率压力场敏感系数的计算结果构造地层渗透参数反演方程,由多井系统井压监测数据实现反演地层渗透参数的计算.算例显示:反演方法对均匀(或分块均匀)油藏模型的计算取得了较好的结果,反演迭代10次后计算结果与模型参数的最大相对误差收敛于1%之内.该方法对油藏动态模拟研究及实现油藏参数动态跟踪具有实际意义.     

Oxygen permeability and stability of Ba0.5Sr0.5Co0.8Fe0.2O3−δ as an oxygen-permeable membrane at high pressures

Oxygen permeation fluxes across the dense Ba_0.5Sr_0.5Co_0.8Fe_0.2O_3−δ (BSCFO) membrane disks were measured under an air/helium oxygen partial pressure gradient at high pressures (up to 10 atm) and various temperatures (973–1123 K). The fabricated BSCFO membrane exhibited good oxygen permeability with a high oxygen permeation flux of 2.01 ml min^− 1cm^− 2 (thickness: 1.37 mm) at 1123 K and 10 atm. Oxygen permeation results were analyzed theoretically using the surface exchange current model. The dependences of the oxygen permeation fluxes on the oxygen partial pressure gradient, suggested that the bulk oxygen ionic diffusion was the rate-limiting step for the overall oxygen permeation process across the BSCFO membrane. The ambipolar diffusion coefficients (D_a), the oxygen vacancy diffusion coefficients (D_v) and the oxygen ionic conductivities (σ_i) of the BSCFO material at different temperatures (973–1123 K) were calculated. It was found that BSCFO possessed high oxygen diffusion coefficients and ionic conductivities, which resulted in the good oxygen permeability of BSCFO. In addition, the BSCFO membrane exhibited good stability of oxygen permeation at 1123 K, while the deterioration of oxygen permeation stability was observed at 1098 K due to structural changes occurring at the surface of the BSCFO membrane disk as demonstrated by XRD.     

Europium Coordination Complexes as Potential Anticancer Drugs: Their Partitioning and Permeation Into Lipid Bilayers as Revealed by Pyrene Fluorescence Quenching

The present study was undertaken to evaluate the membrane-associating properties of a series of novel antitumor agents, Eu(III) coordination complexes (EC), using the pyrene fluorescence quenching as an analytical instrument. Analysis of EC-induced decrease in pyrene fluorescence intensity in terms of partition and solubility-diffusion models allowed us to evaluate the partition and permeation coefficients of the examined compounds into the lipid vesicles prepared from zwitterionic lipid phosphatidylcholine (PC) and its mixtures with cholesterol (Chol) and anionic lipid cardiolipin (CL). The drug-lipid interactions were found to have the complex nature determined by both EC structure and lipid bilayer composition. High values of the obtained partition and permeation coefficients create the background for the development of EC liposomal formulations.     

Magnetic resonance imaging dynamic contrast enhancement (DCE) characteristics of healed myocardial infarction differ from viable myocardium

Purpose

To determine whether healed myocardial infarction alters dynamic contrast-enhancement (DCE) curve shapes as well as late gadolinium-enhancement (LGE).

Materials and methods

Twenty patients with chronic myocardial infarction underwent MR imaging at 1.5 T with blood and myocardial T1 measurements before and after contrast administration for forty minutes. Viable and infarcted myocardial partition coefficients were calculated using multipoint slope methods for ten different DCE sampling intervals and windows. Partition coefficients and coefficients of determination were compared with paired statistical tests to assess the linearity of DCE curve shapes over the 40 min time period.

Results

Calculated partition coefficients did not vary significantly between methods (p = 0.325) for viable myocardium but did differ for infarcted myocardium (p < 0.001), indicating a difference in infarcted DCE. There was a significant difference between viable and infarcted myocardial partition coefficients estimates for all methods with the exception of methods that included measurements during the first 10 min after contrast agent administration.

Conclusion

Myocardial partition coefficients calculated from a slope calculation vary in healed myocardial infarction based on the selection of samples due to non-linear DCE curve shapes. Partition coefficient calculations are insensitive to data sampling effects in viable myocardium due to linear DCE curve shapes.     

Photoluminescence of supernatant liquid of washed erythrocytes upon ultraviolet excitation

In this paper, we present the results of the study of supernatant liquid of washed erythrocytes by the photoluminescence upon ultraviolet excitation. The spectra of intrinsic photoluminescence of an aqueous solution of “Sodium adenosine triphosphate-Vial” (Na₂ATP) were compared with the spectra of supernatant liquid of erythrocytes with added Na₂ATP, glucose, and without additional substances. The results of the comparison suggest that ATP emerging from washed erythrocytes into environment can be recorded in supernatant liquid.     

A density functional study of small AlxOy (x,y=1-4) clusters and their thermodynamic properties

We report thermodynamic properties of small aluminium oxide clusters of mixed stoichiometric ratio AlxOy (x,y=1-4). The rigid rotator-harmonic oscillator approximation is used to calculate the partition function as it is generally applied in thermodynamic studies of polyatomic molecules. The molecular data used to set up the partition functions were computed by density functional techniques employing the BP86 gradient corrected exchange correlation functional. Thereby, the results of three species viz. AlO4, Al4O2, and Al4O3 previously not reported in the literature are included in this study. Equilibrium geometric parameters, energies, selected harmonic vibrational wave numbers of energetically low–lying stationary points are presented along with corresponding absorption coefficients. The resulting thermodynamic functions of aluminium oxides are consistent with the JANAF thermochemical data compilation. These functions are used to determine the temperature dependent chemical equilibrium partial pressure distributions for different aluminium to oxygen ratios.