Ultraviolet C radiation influences the robustness of RNA integrity measurement

The analytical and clinical validity of analyses of RNA samples destined for clinical diagnosis and therapeutic management is directly impacted by RNA quality. RNA is affected by heat, enzymatic degradation, and Ultraviolet (UV) light. RNA from three eukaryotic cell lines was degraded by heat, RNase, or UV light. RNA integrity values obtained with the benchmark Agilent Bioanalyzer 2100 system were compared with those from the more recent QIAxcel Advanced system. The application of this novel method has allowed us to unravel differences between RNA biophysical and biochemical degradation modes. Agilent RNA integrity number (RIN) and QIAxcel RIS were comparable in heat‐degraded and RNase III‐degraded RNA. Agilent RIN and QIAxcel RIS were comparable at a RIN decision level of 7 in UV‐degraded RNA but not overall. The QIAxcel RIS method was more precise than Agilent RIN for RIN<8, while the inverse was true for RIN≥8. Greater degradation of mRNA and rRNA in UV‐damaged samples hampered the Agilent RIN calculation algorithm. Overall, RIS was more robust than RIN for assessing RNA integrity. The ΔΔCt‐values for heat‐ and UV‐degraded RNA samples showed slightly higher correlation with RIS than with RIN. RNA integrity can be used to categorize RNA samples for suitability for downstream gene expression analyses, independently of the RNA degradation mechanism. The new method QIAxcel is more robust and therefore allows more accurate categorization of compromised RNA samples.     

Changes in the intracellular Ca2+ content in human red blood cells in the presence of glycerol

Changes of the intracellular Ca2+ content in human red blood cells (RBCs) in glycerol-containing solutions and after freeze-thawing the cells with glycerol and subsequent deglycerolization were investigated with the Ca2+-sensitive fluorescent dye fluo-4 using fluorescence microscopy. In the glycerol-containing solutions the Ca2+ content increased when compared with a physiological medium (Hepes buffered saline solution (HBSS)). This effect was most likely a result of an inhibition of the Ca2+ pump. After inhibiting the Ca2+ pump using o-vanadate, the Ca2+ uptake was not significantly different in the cells in glycerol-containing and physiological medium. Freeze-thawing and deglycerolization of RBCs resulted in a more pronounced increase in the Ca2+ content. Also in this case, the Ca2+ pump seemed to play a major role.     

THE EFFECT OF ACIDS ON THE INFRARED SPECTRA OF SCHIFF BASES—II. IMINES CONTAINING THE C=C-C=N AND C=C-C=C-C=N UNITS

Abstract— The Fourier-transform infrared spectra of chloroform-d solutions of conjugated imines CH₃CH=CHCH=NCH(CH₃)₂ and CH₃CH₂CH=CHCH=CHCH=NCH(CH₃)₂ and the related protonated species with HCl, HBr, HI, trichloro, dichloro, monobromo and monochloroacetic acids or propionic acid are presented. The effects of conjugation and protonation are examined. The results show that conjugation slightly increases the basicity of the Schiff bases. HCl, HBr and HI protonate the Schiff bases completely. The carboxylic acids protonate partially depending on their p K _a, values. When the Schiff base contains two (or more) C=C bonds conjugated with C=N, the main C=C stretching band undergoes a strong intensification showing that sizeable dipole moment variations occur along the conjugated chain.     

Specific features of the structure and dielectric relaxation of PbWO<Subscript>4</Subscript> in the temperature range 20≤<Emphasis Type="Italic">T</Emphasis>≤550°C

An anomaly of the relaxor type is revealed in the permittivity of the PbWO₄ compound at a temperature of 370°C. This anomaly is associated with the local random displacements of lead and tungsten atoms in the nearest environment of oxygen atoms.     

Radiographic study of the phase formation process in obtaining KNbO3

Instability in the formation of KNbO₃ with perovskite structure is complicated by its structural instability. The structural instability accounts for the existence of phases different in their symmetry and cell parameters (rhombic, tetragonal, and cubic) at room temperature. Original Russian Text Copyright ? 2009 by Yu. A. Kuprina, P. Yu. Teslenko, N. B. Kofanova, M. F. Kupriyanov, and Yu. V. Kabirov __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 3, pp. 582–586, May–June, 2009.     

Specific features of structural states in the BiFeO<Subscript>3</Subscript>-YMnO<Subscript>3</Subscript> solid solutions

The (1 − x)BiFeO_3−x YMnO₃ solid solutions have been found to undergo the following sequence of phase transformations with increasing x: R3c → Pbnm → C2 → Pnma → P6₃ cm. It has been established that the Pbnm and Pnma phases have different orientations of atomic displacements and can exhibit antiferroelectric properties.     

Biochemical and immunochemical study of a protein preparation from the culture liquid ofYersinia pseudotuberculosis

Using ultrafiltration methods of isolation, a culture liquid ofY. pseudotuberculosis has yielded a protein fraction with a molecular mass of not less than 80–100 kDa which possesses hemagglutinating activity and the properties of an antireceptor. It has been shown for the first time by the methods of affinity chromatography, indirect hemagglutination, and indirect IEA that this protein preparation from aY. pseudotuberculosis culture interacts specifically with the Fab₂ fragment of normal human IgG.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Division of the Russian Academy of Sciences, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 784–787, November–December, 1994.     

Phase transitions in manganese-containing perovskites

Solid solutions with a perovskite structure of the general formula A′_1?xA″_xMnO₃ (including the previously unknown compounds with A′=La or Pr and A″=Cd or Bi) are studied. It is found that the structure of the orthorhombic phases formed from rhombohedral phases with a decrease in the temperature is characterized by strong anisotropy of the Mn-O bond lengths. This anisotropy drastically decreases at lower temperatures.     

Modifying the properties of lead titanate in PbTi<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>3</Subscript> solid solutions

Spontaneous deformation in the PbTi_{1 − x} Mn _x O₃ system at room temperature is found to decrease as x increases, indicating a drop in the temperature of the ferroelectric phase transition.     

Phase equilibria in Pr0.7Cd0.3MnO3 and Pr0.7Bi0.3MnO3

A solid state synthesis and phase transitions of solid solutions Pr_0.7Cd_0.3MnO₃ (PCM) and Pr_0.7Bi_0.3MnO₃ (PBM) have been studied within 20–1150°C temperature range. At room temperature, PCM and PBM phases are rhombic within Pnma space group. At high temperatures, Mn-O bonds in PCM are highly anisotropic, the anisotropy becoming insignificant at low temperatures.