Retention behavior of carbohydrates on metal loaded chelating stationary phase under conditions of hydrophilic interaction liquid chromatography.

The chromatographic retention of carbohydrates on chelating stationary phase loaded with different metal ions was studied under conditions of hydrophilic interaction chromatography (HILIC). The chelating stationary phases represented silica microparticles with immobilized 2-hydroxyethyliminodiacetic acid (HEIDA) groups in loose form and saturated with Ca2+, Pb2+, and La3+form. The role of loaded metal ion, the acetonitrile and methanol content in the mobile phase, buffer pH and column temperature on the retention of l-(+)-arabinose, d-(+)-maltose, l-(+)-rhamnose, d-(+)-lactose, d-(+)-xylose, glucose, fructose, sucrose, mannose, maltotriose and d-(+) raffinose was studied. The investigation was mainly focused on possible contribution of the complexation in the stationary phase on retention of carbohydrates as well as on effect of the presence metal ion in HEIDA-silica on resulting HILIC behavior of. It is shown that adsorbents with immobilized metal complexes have a good potential for the separation of organic ligands under HILIC mode.

Precision determination of absolute neutron flux.

A technique for establishing the total neutron rate of a highly-collimated monochromatic cold neutron beam was demonstrated using an alpha-gamma counter. The method involves only the counting of measured rates and is independent of neutron cross sections, decay chain branching ratios, and neutron beam energy. For the measurement, a target of 10B-enriched boron carbide totally absorbed the neutrons in a monochromatic beam, and the rate of absorbed neutrons was determined by counting 478 keV gamma rays from neutron capture on 10B with calibrated high-purity germanium detectors. A second measurement based on Bragg diffraction from a perfect silicon crystal was performed to determine the mean de Broglie wavelength of the beam to a precision of 0.024%. With these measurements, the detection efficiency of a neutron monitor based on neutron absorption on 6Li was determined to an overall uncertainty of 0.058%. We discuss the principle of the alpha-gamma method and present details of how the measurement was performed including the systematic effects. We also describe how this method may be used for applications in neutron dosimetry and metrology, fundamental neutron physics, and neutron cross section measurements.

aCORN: An experiment to measure the electron-antineutrino correlation coefficient in free neutron decay.

We describe an apparatus used to measure the electron-antineutrino angular correlation coefficient in free neutron decay. The apparatus employs a novel measurement technique in which the angular correlation is converted into a proton time-of-flight asymmetry that is counted directly, avoiding the need for proton spectroscopy. Details of the method, apparatus, detectors, data acquisition, and data reduction scheme are presented, along with a discussion of the important systematic effects.

The aCORN Backscatter-Suppressed Beta Spectrometer.

Backscatter of electrons from a beta spectrometer, with incomplete energy deposition, can lead to undesirable effects in many types of experiments. We present and discuss the design and operation of a backscatter-suppressed beta spectrometer that was developed as part of a program to measure the electronantineutrino correlation coefficient in neutron beta decay (aCORN). An array of backscatter veto detectors surrounds a plastic scintillator beta energy detector. The spectrometer contains an axial magnetic field gradient, so electrons are efficiently admitted but have a low probability for escaping back through the entrance after backscattering. The design, construction, calibration, and performance of the spectrometer are discussed.

Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy.

The origin of the martensitic transition in the magnetic shape memory alloy Ni-Mn-Ga has been widely discussed. While several studies suggest it is electronically driven, the adaptive martensite model reproduced the peculiar nonharmonic lattice modulation. We used femtosecond spectroscopy to probe the temperature and doping dependence of collective modes, and scanning tunneling microscopy revealed the corresponding static modulations. We show that the martensitic phase can be described by a complex charge-density wave tuned by magnetic ordering and strong electron-lattice coupling.

High-efficiency cascaded Raman fiber laser with random distributed feedback.

Cascaded lasing provided by Raman gain (at 1115-nm pumping) and random distributed feedback (via Rayleigh backscattering) in a 1.65-km phosphosilicate fiber is studied. Output power for the second Stokes component (1398 nm) exceeds 5 W at pump power of 11 W. In contrast to conventional cascaded Raman laser with high-Q cavity for the intermediate first Stokes component, there is no cavity here and no cavity losses, correspondingly. Longitudinal power distribution is shown to be quite different also. As a result, the efficiency of pump to 2nd Stokes wave conversion is not influenced by the intermediate stage and depends only on the integral attenuation in the fiber. Herewith, the number of generated 2nd Stokes photons at the output may even exceed the absorbed pump photons due to the lower attenuation of Stokes waves.

Improved determination of the neutron lifetime.

The most precise determination of the neutron lifetime using the beam method was completed in 2005 and reported a result of τ(n)=(886.3±1.2[stat]±3.2[syst]) s. The dominant uncertainties were attributed to the absolute determination of the fluence of the neutron beam (2.7 s). The fluence was measured with a neutron monitor that counted the neutron-induced charged particles from absorption in a thin, well-characterized 6Li deposit. The detection efficiency of the monitor was calculated from the areal density of the deposit, the detector solid angle, and the evaluated nuclear data file, ENDF/B-VI 6Li(n,t)4He thermal neutron cross section. In the current work, we measure the detection efficiency of the same monitor used in the neutron lifetime measurement with a second, totally absorbing neutron detector. This direct approach does not rely on the 6Li(n,t)4He cross section or any other nuclear data. The detection efficiency is consistent with the value used in 2005 but is measured with a precision of 0.057%, which represents a fivefold improvement in the uncertainty. We verify the temporal stability of the neutron monitor through ancillary measurements, allowing us to apply the measured neutron monitor efficiency to the lifetime result from the 2005 experiment. The updated lifetime is τ(n)=(887.7±1.2[stat]±1.9[syst]) s.

[Synthesis of spyropyran derivatives of retinal and study of their interaction with bacterioopsin from Halobacterium salinarum].

The synthesis of retinal analogue series that contain a spyropyran moiety instead of a trimethylcyclohexene ring was proposed. The process of the retinal analogue interaction with bacterioopsin from apomembranes of Halobacterium salinarum and the spectral properties of the newly formed pigments were studied. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2008, vol. 34, no. 2; see also http://www.maik.ru.

[The role of emotional pressure in the development of the early forms of chronic cerebrovascular insufficiency]. / Rol' émotsional'nogo napriazheniia v razvitii nachal'nykh form khronicheskoi tserebrovasculiarnoi nedostatochnosti.

The paper presents a comparative analysis of the results of biochemical, neuropsychological and neurophysiological examination of initial chronic cerebrovascular insufficiency in patients without significant psycho-emotional tension (the 1-st group--37 individuals) and with significant emotional tension (the 2-nd group--44 persons). Statistically significant differences between the groups concerned both cerebral hemodynamic parameters and EEG data. On the basis of the results obtained several possible pathogenetic variations of chronic cerebral circulatory insufficiency are suggested on the domination of either primary damages of the structures of the brain and its vessels or the secondary disorder of energetic metabolism and cerebral blood circulation. That, in turn, may be conditioned both by supertension of cerebral systems in chronic stress, and by somatic disturbances. More precise definition of the main pathogenetic factors of initial chronic cerebrovascular insufficiency may be useful for improving efficiency of rehabilitation in these patients.

Human immunodeficiency virus type 1 Vpr alters bone marrow cell function.

Vpr, a 96 amino acid protein, encoded by the human immunodeficiency virus type I (HIV-1), is important for efficient infection of mononuclear phagocytic cells. These cells are abundant in whole bone marrow, which can easily be cultured in vitro to support hematopoiesis. Our experiments indicate that Vpr plays a role in the potent activation of murine and human mononuclear phagocytic cells within a hematopoietic microenvironment. In murine cultures, avid erythrophagocytosis is triggered by transduction of marrow cells with supernatant derived from PA317 cells transfected with a murine retroviral delivery vector bearing a Vpr expression cassette. Supernatants derived from cells transfected with the same vector carrying sequences for the expression of other relevant viral and nonviral proteins do not induce erythrophagocytosis to any marked degree. The effect on human marrow cells is similar, where treatment promotes adhesion of mononuclear phagocytic cells to culture plates in association with other nucleated and nonnucleated cells that undergo subsequent engulfment. The differential effects of Vpr point and deletion mutants in both marrow culture systems fortify the view that the effect is specific to HIV-1 Vpr. Addition of low molar quantities of purified Vpr to marrow cultures is also capable of promoting cell adhesion and phagocytosis, suggesting that extracellular Vpr is the effector of the phenomenon. Accelerated phagocytosis is a hallmark of promonocyte, monocyte, and macrophage activation and its occurrence within a hematopoietic microenvironment may account for critical in vivo pathogenic features of HIV-1 infection. First, activation of mononuclear phagocytes may promote productive viral infection; and second, premature phagocytosis could provide, at least in part, a molecular explanation for the induction of the idiopathic cytopenias that are typical of individuals infected with HIV-1.

Marrow stromal cells as a source of progenitor cells for nonhematopoietic tissues in transgenic mice with a phenotype of osteogenesis imperfecta.

Marrow stromal cells from wild-type mice were infused into transgenic mice that had a phenotype of fragile bones resembling osteogenesis imperfecta because they expressed a human minigene for type I collagen. In mice that were irradiated with potentially lethal levels (700 cGy) or sublethal levels (350 cGy), DNA from the donor marrow stromal cells was detected consistently in marrow, bone, cartilage, and lung either 1 or 2.5 mo after the infusions. The DNA also was detected but less frequently in the spleen, brain, and skin. There was a small but statistically significant increase in both collagen content and mineral content of bone 1 mo after the infusion. Similar results were obtained with infusion of relatively large amounts of wild-type whole marrow cells into the transgenic mice. In experiments in which male marrow stromal cells were infused into a female osteogenesis imperfecta-transgenic mouse, fluorescense in situ hybridization assays for the Y chromosome indicated that, after 2.5 mo, donor male cells accounted for 4-19% of the fibroblasts or fibroblast-like cells obtained in primary cultures of the lung, calvaria, cartilage, long bone, tail, and skin. In a parallel experiment in which whole marrow cells from a male mouse were infused into a female immunodeficient rag-2 mouse, donor male cells accounted for 4-6% of the fibroblasts or fibroblast-like cells in primary cultures. The results support previous suggestions that marrow stromal cells or related cells in marrow serve as a source for continual renewal of cells in a number of nonhematopoietic tissues.

Specific inhibition of expression of a human collagen gene (COL1A1) with modified antisense oligonucleotides. The most effective target sites are clustered in double-stranded regions of the predicted secondary structure for the mRNA.

A series of antisense oligonucleotides (ASOs) were synthesized and tested to define the best target sites within an RNA transcript of collagen for effective inhibition of expression. The test system consisted of mouse NIH 3T3 fibroblasts that were stably transfected with a human minigene for procollagen I so that the cells simultaneously synthesized full-length mouse pro alpha 1 (I) chains and internally deleted human pro alpha 1 (I) chains. The sequences of the transcripts from both genes were compared, and a series of 28 ASOs were designed to target sites in which there were at least two base differences within a 20-nucleotide sequence between the human and mouse transcripts. Six of the ASOs specifically decreased the levels of pro alpha 1 (I) chain synthesized from the human gene without a decrease in the levels of pro alpha 1 (I) chains from the mouse endogenous gene. The most effective ASOs reduced the intracellular levels of human pro alpha 1 (I) chains relative to the mouse pro alpha 1 (I) chains to 37-67% of the control values. Combined addition of two effective ASOs or a second administration of the same effective ASO did not produce any additive effect. The results did not support previous suggestions that the best target sites for ASOs were sequences around initiation codons for translation, at intron-exon boundaries, or in single-stranded loops in hairpin structures. Also, the results did not support previous suggestions that the most effective ASOs are those with the highest affinities for their target sequences. Instead, the most consistent pattern in the data was that the most effective ASOs were those targeted to sequences that were predicted to form clustered double-stranded structures in RNA transcripts.

[Search for new products of gene expression in human cardiac muscle. Microsequencing of proteins after two-dimensional electrophoresis]. / Poisk novykh produktov gennoi ékspressii v serdechnoi myshtse cheloveka. Mikrosekvenirovanie belkov posle dvumernogo élektroforeza.

Proteins of the human heart muscle were studied using modified two-dimensional electrophoresis. After separation, proteins were electroblotted onto Immobilon P membranes and several protein spots were used for microsequencing analysis. In most cases the proteins analyzed have blocked N-terminal amino acids. In order to study the primary structure of these proteins, hydrolysis in situ by trypsin followed by reversed-phase HPLC and microsequencing of the resulting peptides were performed. Four protein were identified in 8 analyzed fractions, specifically myosin light chain 1 (MLCl-V/sB), fatty-acid binding protein (heart isoform), alpha (B)-crystallin and alpha-tropomyosin. Amino acid sequences of two proteins were not found among human amino acid sequences collected in SWISSPROT bank (v. 21).

Identification of an allelic variant of isoform MLC1-V/sB (human myosin light chain).

A study of 250 specimens of human myocardium by two-dimensional gel electrophoresis revealed an allelic variant of isoform MLC1-V/sB, which was identified by immunoblotting with monoclonal antibody against MLC1-V/sB and peptide mapping after in situ tryptic digestion of electroblotted proteins. The substitution Asn-144 for His-144 was found in this new allelic variant of MLC1-V/sB.

Membrane-bound phenylalanine hydroxylase of human liver.

Phenylalanine hydroxylase (EC 1.14.16.1) antigen and activity have been identified among proteins extracted with a buffer containing 0.4% Triton X-100 from adult human liver bioptate fraction, which was sedimented at 105,000 x g (n = 4). This enzyme fraction was designated as a 'membrane-bound form of phenylalanine hydroxylase'. It amounted to 5-15% of phenylalanine hydroxylase activity and 15-25% of phenylalanine hydroxylase antigen content. After immunoblotting two-dimensional gels, the soluble (cytoplasmic) form of phenylalanine hydroxylase antigen displayed three spots: one spot corresponded to the L-subunit with a molecular weight of 55,000, the two other spots corresponded to the H-subunit with a molecular weight of 57,000. Only the L-subunit was revealed in the membrane-bound enzyme form. Both phenylalanine hydroxylase activity and antigen were also demonstrated in extracts from human embryonic livers (n = 7). However, in this case the membrane-bound phenylalanine hydroxylase amounted to 85% of the antigen content. Subunit compositions of the enzymes were similar in adult and embryonic livers. The differences in the subunit compositions and enzyme activities of membrane-bound and cytoplasmic forms of phenylalanine hydroxylase in adults and embryos may be due to other functions of this enzyme in the hepatocyte membrane.

[Identification of alpha-tropomyosin of the human myocardium by two-dimensional electrophoresis, and sequencing]. / Identifikatsiia alpha-tropomiozina serdechnoi myshtsy cheloveka dvumernym élektroforezom i sekvenirovaniem.

Two-dimensional electrophoresis of total cardiac muscle extracts allows the detection of about 200 protein fractions. In preliminary studies the fraction D-10 protein was characterized in terms of relative molecular mass, isoelectric point and quantitative composition as alpha-tropomyosin. The similarity of the protein to human alpha-tropomyosin was confirmed by the results of analysis of the N-terminal sequence of the D-10 protein eluate in a gas-phase sequencer.

[The dynamics of the properties of liver phenylalanine hydroxylase in human embryogenesis]. / Dinamika svoistv fenilalaningidroksilazy pecheni v émbriogeneze cheloveka.

Content, subunit composition and activity of phenylalanine hydroxylase's (PH) (EC 1.14.16.1) in cytoplasmic and membrane proteins extract of embryonic liver on week 6-11 of pregnancy were studied. PH enzymatic and antigenic activities were detected starting from the week 6 of pregnancy. Liver cytoplasmic PH antigen content increased gradually during development while its enzymatic activity remained practically unchanged. Concomitantly, relative content of L-subunit increased. Content of liver membrane PH antigen was constant during development. Samples of liver with relatively low specific PH activity were characterized by high content of PH in cytoplasm and vice versa. Since PH activity in extracts prepared from mixture of these samples decreased, an unknown PH inhibitor must be present in cytoplasmic protein extracts with relatively low specific PH activity.

[Immunochemical detection and characteristics of the subunit composition of phenylalanine hydroxylase in the brain of man]. / Immunokhimicheskoe vyiavlenie i kharakteristika sub"edinichnogo sostava fenilalaningidroksilazy v mozge cheloveka.

Immunochemical properties and subunit structure of an antigen were characterized in autopsy specimens of human liver and brain, using antiserum against human phenylalanine hydroxylase. An identical antigen was revealed in extracts of organs by immunoelectrophoresis. Its content was 1.5-2.0 mg/g tissue in the liver and 20-40 micrograms/g tissue in the brain. One L enzyme subunit and two H subunits were identified in the liver extracts after two-dimensional electrophoresis followed by immunoblotting. Subunit structure of phenylalanine hydroxylase in the brain was similar to that in the liver. The molecular weight of L subunit was 55,000 and it was located in the same area as albumin isoforms. The molecular weight of H subunits was 57,000 and they differed from L subunits in pI. The antigen was purified from crude extracts of biopsy liver by affinity chromatography on immunoadsorbent to phenylalanine hydroxylase and showed phenylalanine hydroxylase activity. An antigen with similar molecular weight was also purified from the brain extract by the same method. These data suggest that phenylalanine hydroxylase can be present in the human brain.

[Phenylalanine hydroxylase of human embryos: its homology with the enzyme from the liver of adults]. / Fenilalaningidroksilaza émbrionov cheloveka: gomologiia s fermentom iz pecheni vzroslykh liudei.

Phenylalanine hydroxylase (PH) activity was discovered in the liver of 7-12 week old human embryos. Embryonic and adult PHs were identical, as shown by immunoelectrophoresis. Unlike the adult liver PH, the PH content of the extract of cytoplasmic proteins of embryonic liver was reduced but the specific activity was increased more than by one order of magnitude. H (57,000 D) and L (55,000 D) subunits were detected by immunoblotting. The L subunit predominates in the extract of membrane proteins of embryonic liver. Hence, the major part of phenylalanine oxidizing activity in the embryonic liver is related to the enzyme immunochemically identical with the PH of adult liver but differing from it in some structural and functional properties.

[Immunochemical detection of phenylalanine hydroxylase in extracts of various human organs]. / Immunokhimicheskoe vyiavlenie fenilalaningidroksilazy v ékstraktakh nekotorykh organov cheloveka.

Phenylalanine hydroxylase was found in extracts from autoptates of human liver, kidney, myocardium, small intestine, lung and spleen. In all the tissues studied, except of spleen, the antigen was detected by immunoelectrophoresis with monospecific antiserum against human liver phenylalanine hydroxylase. As shown by immunoblotting carried out after electrophoresis under denaturating conditions, the antigen, observed in various tissues, exhibited similar electrophoretic mobility which was very close to that of the enzyme purified from human liver tissue. Molecular mass of revealed antigen was estimated 55-57 kDa. Coincidence of immunochemical and chemical properties of the protein suggested that the antigen, detected in the tissue extracts, was a product of phenylalanine hydroxylase gene expression. The antigen concentration did not correlate with the content of albumin in tissue extracts, thus demonstrating that the revealed antigen did not occur in these preparations with blood contaminations. Content of the antigen in the tissue extracts studied was (ug per g): liver - 1500-1900, kidney - 300-575, brain - 20-40, myocardium - 85-105, lung - 40-125, small intestine - 45-70, spleen - 0-12.