Does local cryotherapy improve thermal diagnosis similar to whole-body cryotherapy in spinal diseases?

Thermal imaging has been used for patients with spinal diseases who were qualified by their physicians for whole-body treatment or local cryotherapy. The experimental groups of patients consisted of 20 males aged 51.6 ± 9.0 (12 treated by whole-body cryotherapy and 8 by local cryotherapy). The distribution of the skin surface temperature was monitored by using a Thermovision Camera E60 before and immediately after body cooling. The chosen spinal region (Th5/Th6–L5/S1) was taken into consideration for all of the research groups. An essential drop in skin temperature and a better differentiation of the body surface temperatures (leading to an increase in the diagnostic value of thermography) was observed after both methods of cold impact. In order to estimate the usefulness of thermovision used after body cooling, the quantitative parameters including temperature contrast—the difference between the maximum and minimum temperatures before and after cold impact and relative contrast ratio (related to the average temperature of the selected area of interest, before and after cooling, respectively)—were compared for both kinds of medical treatment. The statistical analysis proved that significant differences between the parameters obtained before and after body cooling in the case that patients treated by local and whole-body cryotherapy are similar. However, local therapy is cheaper and easy for application while whole-body therapy can give more information about the state of soft tissues for the whole back.     

The effect of polysialic acid on molecular dynamics of model membranes studied by 31P NMR spectroscopy

The paper reports the results of our study on the dynamics of model phospholipid membranes studied by 31P NMR spectroscopy. The 31P NMR spectra of multilamellar vesicles in temperatures below the main phase transition of PC are reported. The 31P NMR spectra revealed changes caused by an increase of the membrane fluidity when polysialic acid (polySia) was applied as a modifying agent. The presence of polySia in the external environment of the phospholipid vesicles changes the motional freedom in the region of phosphate group of lipids. Increase of polysialic acid concentration changes structural properties of a membrane by increasing its fluidity.     

Novel sample treatment procedures for the determination of phosphorus in Cu‐based alloys using X‐ray fluorescence spectrometry to solve the microstructural effect issue

The accurate analysis of hard CuP and CuPAg‐type solders using X‐ray fluorescence spectrometry is a difficult task. Surface milling, the most common sample preparation method for calibration materials, results in poor accuracy for the phosphorus analysis, as evidenced by the unacceptable values of the root mean square error. Meanwhile, the analysis of real samples provides incorrect results, and microstructural effects are the main source of error. Thus, this effect was negated by considering the information depth of the phosphorus Kα line and the microstructure size of the alloys. Phosphorus was measured using a thin layer of the sample (a thickness of several micrometers). As a result, the analyzed layer was a poor representative of the sample. Two different approaches for solving the microstructural effect issue were proposed. In the first method, the alloy was remelted under controlled conditions to obtain fine‐grain samples, which successfully limited the microstructural effects. The second solution used specially prepared thin layer samples, and the sample dissolution eliminated the microstructural effect. Using the developed sample treatment methods resulted in an improvement in the accuracy of the phosphorus calibration curves. This allowed for the correct determination of phosphorus and other alloying elements in the Cu‐based alloys with low uncertainties.     

Synthesis, mesomorphic and optical properties of isothiocyanatotolanes

The synthesis, mesomorphic properties and UV absorption spectra of laterally fluorine substituted, and the corresponding unsubstituted, 4'-alkyl-, 4'-alkoxy-, 4'-alkylcyclohexyl-, 4'-alkylbicyclo [2,2,2]octyl- and 4'-alkylcyclohexylethyl-4-isothiocyanatotolanes are described. Multicomponent broad range nematic mixtures with birefringence values higher than 0.4 and moderate viscosities are developed.     

Capillary Condensation in Pores with Energetically Heterogeneous Walls: Density Functional versus Monte Carlo Calculations

We investigate adsorption of a Lennard-Jones fluid in slit-like pores with energetically heterogeneous walls by using Grand Canonical Monte Carlo simulations and a density functional approach. The model of a fluid-wall potential is qualitatively similar to that invoked by R?cken et al. (J. Chem. Phys. 108, 8089, (1999); i.e., it consists of a homogeneous part that varies in the direction perpendicular to the wall and a periodic part, varying also in one direction parallel to the wall, but in contrast to the above mentioned work, both parts of the fluid-wall potential are modeled by Lennard-Jones (9, 3) type functions. The structure of the adsorbed film is characterized by local densities. We evaluate the phase diagrams for several systems characterized by different corrugation of the adsorbing potential and discuss the discrepancies between theoretical predictions and computer simulations. Copyright 2001 Academic Press.     

Adsorption of acetone on the mercury electrode from H2O+(CH3)2CO+HCl solutions

The adsorption of acetone on a mercury electrode from (CH₃)₂CO+H₂O+HCl solutions has been studied using a thermodynamically rigorous procedure. The chemical potential of the supporting electrolyte has been kept constant by using the concentrations corresponding to the constant e.m.f. of the cell with electrodes reversible to each of the ions in the solutions. It is suggested that the molecule is to some extent oriented with the hydrocarbon part towards mercury. The composition of the surface layer has been calculated.     

Thermal stability study of the protease inhibitors

A thermal and kinetic analysis of two protease inhibitors: nelfinavir mesylate and atazanavir sulfate, were carried out to find their thermal stability. DSC curves of both drugs showed exothermic transition. This observed process resulted in two steps. Obtained apparent activation energy pointed at low stability of studied protease inhibitors in water solutions.     

Stability and nature of complexes of the type MCl+ in aqueous solution (M=Mn,Co, Ni,and Zn)

Equilibrium constants have been determined both potentiometrically and spectrophotometrically for reactions of the type M²⁺+Cl^??MCl⁺ using aqueous solutions of the corresponding metal perchlorates as the reaction media (M=Mn, Co, Ni, and Zn). The variation in the quotient of the activity coefficients of these reactions with increasing molality of the reaction medium has been found to be approximately the same for the CuCl⁺ (previously studied), MnCl⁺, and ZnCl⁺ complexes, while a different dependence is observed for the CoCl⁺ and NiCl⁺ complexes. The results are interpreted as indicating equilibrium coexistence of the [MCl(OH₂)₅]⁺ and {[M(OH₂)₆]Cl}⁺ species in the latter two cases. Approximate values of the corresponding equilibrium constants are estimated in addition to the derived overall thermodynamic stability constants of the MCl⁺ formal complexes. The latter are found to follow a partly inverted Irving-Williams series, the fact being accountable in terms of the ligand field stabilization energy.     

Multiple protonation equilibria in electrostatics of protein-protein binding

All proteins contain groups capable of exchanging protons with their environment. We present here an approach, based on a rigorous thermodynamic cycle and the partition functions for energy levels characterizing protonation states of the associating proteins and their complex, to compute the electrostatic pH-dependent contribution to the free energy of protein-protein binding. The computed electrostatic binding free energies include the pH of the solution as the variable of state, mutual "polarization" of associating proteins reflected as changes in the distribution of their protonation states upon binding and fluctuations between available protonation states. The only fixed property of both proteins is the conformation; the structure of the monomers is kept in the same conformation as they have in the complex structure. As a reference, we use the electrostatic binding free energies obtained from the traditional Poisson-Boltzmann model, computed for a single macromolecular conformation fixed in a given protonation state, appropriate for given solution conditions. The new approach was tested for 12 protein-protein complexes. It is shown that explicit inclusion of protonation degrees of freedom might lead to a substantially different estimation of the electrostatic contribution to the binding free energy than that based on the traditional Poisson-Boltzmann model. This has important implications for the balancing of different contributions to the energetics of protein-protein binding and other related problems, for example, the choice of protein models for Brownian dynamics simulations of their association. Our procedure can be generalized to include conformational degrees of freedom by combining it with molecular dynamics simulations at constant pH. Unfortunately, in practice, a prohibitive factor is an enormous requirement for computer time and power. However, there may be some hope for solving this problem by combining existing constant pH molecular dynamics algorithms with so-called accelerated molecular dynamics algorithms.