Age of the magma chamber and its physicochemical state under Elbrus Greater Caucasus, Russia using zircon petrochronology and modeling insights.

Mount Elbrus, Europe's tallest and largely glaciated volcano, is made of silicic lavas and is known for Holocene eruptions, but the size and state of its magma chamber remain poorly constrained. We report high spatial resolution U-Th-Pb zircon ages, co-registered with oxygen and hafnium isotopic values, span ~ 0.6 Ma in each lava, documenting magmatic initiation that forms the current edifice.

The economic potential of metalliferous sub-volcanic brines.

The transition to a low-carbon economy will increase demand for a wide range of metals, notably copper, which is used extensively in power generation and in electric vehicles. Increased demand will require new, sustainable approaches to copper exploration and extraction. Conventional copper mining entails energy-intensive extraction of relatively low-grade ore from large open pits or underground mines and subsequent ore refining.

Pervasive Hydrothermal Events Associated with Large Igneous Provinces Documented by the Columbia River Basaltic Province.

The degree and extent of crustal hydrothermal alteration related to the eruption of large igneous provinces is poorly known and not easily recognizable in the field. We here report a new δO dataset for dikes and lavas from the Columbia River Basalt Group (16-15 Ma) in the western USA, and document that dikes on average are 1-2‰ more depleted in δO than basalt flows. We show that this observation is best explained with the involvement of heated meteoric  waters during their cooling in the crust.

[Thrombosis of the portal, upper mesenteric, and splenic veins in a patient with thrombophilia (a clinical case report)].

Currently there are several dozens of hereditarily associated thrombophilias and acquired states known to condition the development of a thrombus. Thrombosis of visceral veins appears to be a considerably less often encountered event than thrombosis in the system of visceral arteries. Presented herein in the article is a clinical case report concerning subacute thrombosis of the portal, upper mesenteric and splenic veins, having developed on the background of mutations of 7 genes of the system of haemostasis in a young adult patient.

Photophysics and energy transfer studies of Alq3 confined in the voids of nanoporous anodic alumina.

We report on a hierarchical nanoarchitecture wherein distinct chromophores are deterministically placed at two different types of sites in a nanoporous metal oxide framework. One chromophore, namely Tris(8-hydroxyquinoline)aluminium(III) (Alq3), is embedded in the 1-2 nm sized nanovoids of anodic aluminum oxide (AAO) and another chromophore (carboxyfluorescein or pyrenebutyric acid) is anchored in the form of a monolayer to the surface of the walls of the cylindrical nanopores (- 20 nm in diameter) of AAO. We found the luminescence maximum to occur at 492 nm, blueshifted by at least 18 nm from the value in solutions and thin films.

[Molecular cloning and analysis of cDNA sequences encoding serine proteinase and Kunitz type inhibitor in venom gland of Vipera nikolskii viper].

Serine proteinases and Kunitz type inhibitors are widely represented in venoms of snakes from different genera. During the study of the venoms from snakes inhabiting Russia we have cloned cDNAs encoding new proteins belonging to these protein families. Thus, a new serine proteinase called nikobin was identified in the venom gland of Vipera nikolskii viper.

Surface-enhanced raman scattering (SERS) detection of low concentrations of tryptophan amino acid in silver colloid.

The surface-enhanced Raman scattering (SERS) spectrum of L-tryptophan has been studied in the concentration range 1.4 × 10(-8) to 5 × 10(-4) M. A borohydride-reduced silver colloid was employed as the nanoparticle enhancing agent and different electrolytes have been tested for activation of the colloid.

Optical resolution photoacoustic microscopy using novel high-repetition-rate passively Q-switched microchip and fiber lasers.

Optical-resolution photoacoustic microscopy (OR-PAM) is a novel imaging technology for visualizing optically absorbing superficial structures in vivo with lateral spatial resolution determined by optical focusing rather than acoustic detection. Since scanning of the illumination spot is required, OR-PAM imaging speed is limited by both scanning speed and laser pulse repetition rate. Unfortunately, lasers with high repetition rates and suitable pulse durations and energies are not widely available and can be cost-prohibitive and bulky.

Passively Q-switched Yb3+:NaY(WO4)2 laser with GaAs saturable absorber.

Passively Q-switched Yb(3+):NaY(WO(4))(2) lasers have been demonstrated using a GaAs saturable absorber. Under continuous wave pump mode, significant pulse shortening effects have been observed at high pump powers. At a pump power of 12 W, stable Q-switched output has been obtained with a pulse duration of 5 ns, pulse repetition rate of 83 kHz and a pulse to pulse timing jitter of less than 2%.

High-peak-power subnanosecond passively Q-switched ytterbium-doped fiber laser.

A passively Q-switched ytterbium doped fiber laser has been demonstrated with a Cr(4+):yttrium aluminum garnet saturable absorber and distributed stimulated Brillouin scattering. A linearly polarized output with approximately 375 kW peak power and a pulse duration as short as 490 ps have been obtained. A theoretical model is developed to simulate passive Q switching with the stimulated Brillouin scattering, which shows good agreement with the experiment.

Two-wavelength ytterbium-doped fiber laser with sustained relaxation oscillation.

Dual-wavelength radiation around 1044 nm and 1070 nm has been generated directly from a cladding pumped Yb-doped fiber laser. Outputs of the two wavelengths exhibit sustained relaxation oscillation with anticorrelated dynamics. Modeling of the transient built up of the free-running laser shows the two-wavelength behavior can be attributed to the existence of two gain peaks of Yb-doped fiber under intermediate pump conditions.

[New weak toxins from the cobra venom].

A protein with M 7485 Da containing five disulfide bonds was isolated from the venom of cobra Naja oxiana using various types of liquid chromatography. The complete amino acid sequence of the protein was determined by protein chemistry methods, which permitted us to assign it to the group of weak toxins. This is the first weak toxin isolated from the venom of N.

Two-wavelength passively Q-switched ytterbium doped fiber laser.

A high power passively Q-switched dual wavelength Yb fiber laser using a Cr4+:YAG saturable absorber has been realized. Two wavelengths centered at 1040 nm and 1070 nm are generated directly from the cladding pumped Yb doped fiber laser. The pulse trains exhibit regions of stability and instability dependent on the pump power.

[Natural alpha-conotoxins and their synthetic analogues in studies of nicotinic acetylcholine receptors].

alpha-Conotoxins, peptide neurotoxins from poisonous marine snails of the genus Conus that highly specifically block nicotinic acetylcholine receptors (AChRs) of various types, are reviewed. Preliminarily, the structural organization of AChRs of the muscular and neuronal types, their involvement in physiological processes, and their role in various diseases are briefly discussed. In this connection, the necessity of quantitative determination of AChR subtypes using neurotoxins and other approaches is substantiated.

Clinical use of a simultaneous HPLC assay for indinavir, saquinavir, ritonavir and nelfinavir in children and adults.

PROTEASE INHIBITOR TDM: This study examines the importance of therapeutic drug monitoring (TDM) of protease inhibitors (PI) in adults and children infected with the human immunodeficiency virus (HIV). Pediatric patients were included because information in this population is limited. A high performance liquid chromatographic (HPLC) assay measured indinavir, saquinavir, ritonavir and nelfinavir simultaneously in 0.

Clinical use of a simultaneous HPLC assay for indinavir, saquinavir, ritonavir, and nelfinavir in children and adults.

Protease inhibitor (PI) monitoring may improve the care of human immunodeficiency virus (HIV)-infected patients; however, pediatric data are limited. A high-performance liquid chromatographic (HPLC) assay developed for the simultaneous determination of indinavir, ritonavir, saquinavir, and nelfinavir in 0.2 mL of plasma was used to quantify PI concentrations in HIV patients.

[Sensitive nonradioactive screening method for compounds interacting with alpha7-cholinoreceptor].

A sensitive nonradioactive method for detection of substances interacting with the neuronal nicotinic acetylcholine alpha 7-type receptor (AChR) was proposed. The method uses biotinylated alpha-cobratoxin (Bt-CTX) and is based on the ability of the N-terminal ligand-binding extracellular domain (LBED) of AChR to interact with alpha-cobratoxin (CTX) as does the whole receptor. LBED was produced by heterologic expression of a gene fragment of the alpha 7 subunit of AChR from the rat brain in Escherichia coli cells sorbed on wells of a 96-well plate and incubated with Bt-CTX.

Structural elucidation of metabolites of ritonavir and indinavir by liquid chromatography-mass spectrometry.

The structural elucidation of metabolites of ritonavir and indinavir, HIV-protease inhibitor drugs, by liquid chromatography-electrospray ionization mass spectrometry is described. Ritonavir and indinavir were biotransformed separately by incubation with transplant quality human liver microsomes. The incubation mixture was then analyzed by HPLC coupled to ion trap (ITMS) and triple quadrupole mass analyzers.

[Photoactivatable analogues of alpha-conotoxins GI and MI and their interaction with nicotinic acetylcholine receptor].

Two photoactivatable analogues of alpha-conotoxin GI with the benzoylphenylalanine residue (Bpa) substituted for His10 or Tyr11 were synthesized using the method of solid-phase peptide synthesis. In addition, alpha-conotoxin MI was chemically modified by placing an azidobenzoyl or a benzoylbenzoyl photo label at N alpha of Gly1 or N epsilon of Lys10. All the photoactivatable analogues were purified by HPLC, their structures were confirmed by MALDI MS, and the label positions in their molecules were localized by MS of their trypsinolysis fragments.

[MALDI-mass spectrometry for identification of new proteins in snake venoms].

By MALDI MS, we searched cobra venoms for new low-content polypeptides. A number of new proteins with molecular masses 7-25 kDa, characteristic of the known snake protein toxins, were identified, with the content of one of them less than 0.02%.

[Cobra venom contains a protein belongs to the CRISP family].

Amino acid sequences of several fragments of the 25 k protein (molecular mass 24,953 Da) previously isolated from cobra Naja kaouthia (Kukhtina et al. Bioorg. Khim.

[The weak neurotoxin from Naja kaouthia Cobra venom decreases the arterial blood pressure in rats].

The weak neurotoxin from the Naja kaouthia cobra venom was found to reduce, under the intravenous administration to rats, the arterial blood pressure and increase the heart rate.

[Structure and conformational heterogeneity of the weak toxin from the cobra Naja kaouthia venom].

Resonances in the two-dimensional 1H NMR spectra of a weak toxin (WTX) from the venom of cobra Naja kaouthia for all 65 amino acid residues were assigned. The amino acid sequence of WTX, determined by the sequentional assignment of spin systems, was found to be similar to that of the CM-9a toxin from the N. kaouthia venom.