Multimodal label-free imaging of murine hepatocellular carcinoma with a subcellular resolution.

We demonstrate label-free imaging of genetically induced hepatocellular carcinoma (HCC) in a murine model provided by two- and three-photon fluorescence microscopy of endogenous fluorophores excited at the central wavelengths of 790, 980 and 1250 nm and reinforced by second and third harmonic generation microscopy. We show, that autofluorescence imaging presents abundant information about cell arrangement and lipid accumulation in hepatocytes and hepatic stellate cells (HSCs), harmonics generation microscopy provides a versatile tool for fibrogenesis and steatosis study. Multimodal images may be performed by a single ultrafast laser source at 1250 nm falling in tissue transparency window.

Modeling of the cerebral blood circulation in a capillary network accounting for the influence of the endothelial surface layer.

Background And Objective: The paper describes a mathematical model of blood flow in capillaries with accounting for the endothelial surface layer (ESL).

Method: The influence of ESL is modeled by a boundary layer with zero flow velocity. Finite element modeling and an analytical approach based on the homogenization of the core region of blood flow occupied by erythrocytes are developed to describe the resistance of a capillary.

A rapid room-temperature cloud point extraction for spectrophotometric determination of Copper (II) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium chloride.

The conditions for the surfactant rich phase of Triton X-100 formation and the extraction of Copper (II) as a complex with 6,7-dihydroxy-2,4-diphenylbenzopyrylium chloride at room temperature have been optimized. It was shown that the sodium salt of p-toluic acid can be used as a chemical initiator of cloud point extraction. The optimal conditions for room temperature cloud point extraction were found to be: pH 5.

Multimodal nonlinear-optical imaging of nucleoli.

Multimodal nonlinear microscopy combining third-harmonic generation (THG) with two- and three-photon-excited fluorescence (2PEF and 3PEF) is shown to provide a powerful resource for high-fidelity imaging of nucleoli and nucleolar proteins. We demonstrate that, with a suitably tailored genetically encoded fluorescent stain, the 2PEF/3PEF readout from specific nucleolar proteins can be reliably detected against the extranucleolar 2PEF/3PEF signal, enabling high-contrast imaging of the key nucleolar ribosome biogenesis components, such as fibrillarin. THG is shown to provide a versatile readout for unstained nucleolus imaging in a vast class of biological systems as different as neurons in brain slices and cultured HeLa cells.

Dispersive Liquid-Liquid Semi-Microextraction of Сu(II) with 6,7-dihydroxy-2,4-diphenylbenzopyrylium Chloride for its Spectrophotometric Determination.

A novel dispersive liquid-liquid semi-microextraction (DLLsME) procedure for copper(II) preconcentration is proposed. The system containing copper(II) and 6,7-dihydroxy-2,4-diphenylbenzopyrylium chloride (DHDPhB), after addition a mixture of chloroform and methanol becomes cloudy and the formation of the organic phase was observed immediately. The optimal conditions of DLLsME were found to be: pH 5, absorption band maximum was 570 nm, 1 cm3 of 1×10-3 mol/dm3ofDHDPhB, and mixed extractant containing 1 cm3 of chloroform and 1 cm3 of methanol.

Enhanced-contrast two-photon optogenetic pH sensing and pH-resolved brain imaging.

We present experiments on cell cultures and brain slices that demonstrate two-photon optogenetic pH sensing and pH-resolved brain imaging using a laser driver whose spectrum is carefully tailored to provide the maximum contrast of a ratiometric two-photon fluorescence readout from a high-brightness genetically encoded yellow-fluorescent-protein-based sensor, SypHer3s. Two spectrally isolated components of this laser field are set to induce two-photon-excited fluorescence (2PEF) by driving SypHer3s through one of two excitation pathways-via either the protonated or deprotonated states of its chromophore. With the spectrum of the laser field accurately adjusted for a maximum contrast of these two 2PEF signals, the ratio of their intensities is shown to provide a remarkably broad dynamic range for pH measurements, enabling high-contrast optogenetic deep-brain pH sensing and pH-resolved 2PEF imaging within a vast class of biological systems, ranging from cell cultures to the living brain.

Nonstationary Model of Oxygen Transport in Brain Tissue.

The paper addresses the mathematical study of a nonstationary continuum model describing oxygen propagation in cerebral substance. The model allows to estimate the rate of oxygen saturation and stabilization of oxygen concentration in relatively large parts of cerebral tissue. A theoretical and numerical analysis of the model is performed.

Fast room temperature cloud point extraction procedure for spectrophotometric determination of phosphate in water samples.

A novel fast room temperature cloud point extraction (RT-CPE) procedure for preconcentration and spectrophotometric determination of phosphate based on the heteropoly blue formation was developed. The proposed method includes the formation of yellow molybdoantymonatophosphoric heteropoly complex, its extraction into Triton X-100 micellar phase obtained at room temperature and reduction of heteropoly complex by ascorbic acid solution in ethanol and absorbance measurement of heteropoly blue at 790 nm. Under optimal conditions (1% (v/v) of Triton X-100 and 0.

Cell-specific three-photon-fluorescence brain imaging: neurons, astrocytes, and gliovascular interfaces.

We present brain imaging experiments on rat cortical areas, demonstrating that, when combined with a suitable high-brightness, cell-specific genetically encoded fluorescent marker, three-photon-excited fluorescence (3PEF), enables subcellular-resolution, cell-specific 3D brain imaging that is fully compatible and readily integrable with other nonlinear-optical imaging modalities, including two-photon-fluorescence and harmonic-generation microscopy. With laser excitation provided by sub-100-fs, 1.25-µm laser pulses, cell-specific 3PEF from astrocytes and their processes detected in parallel with a three-photon-resonance-enhanced third harmonic from blood vessels is shown to enable a high-contrast 3D imaging of gliovascular interfaces.

Two- and three-photon absorption cross-section characterization for high-brightness, cell-specific multiphoton fluorescence brain imaging.

We demonstrate an accurate quantitative characterization of absolute two- and three-photon absorption (2PA and 3PA) action cross sections of a genetically encodable fluorescent marker Sypher3s. Both 2PA and 3PA action cross sections of this marker are found to be remarkably high, enabling high-brightness, cell-specific two- and three-photon fluorescence brain imaging. Brain imaging experiments on sliced samples of rat's cortical areas are presented to demonstrate these imaging modalities.

Stain-free subcellular-resolution astrocyte imaging using third-harmonic generation.

We demonstrate stain-free, high-contrast, subcellular-resolution imaging of astroglial cells using epi-detected third-harmonic generation (THG). The astrocyte-imaging capability of THG is verified by colocalizing THG images with fluorescence images of astrocytes expressing a genetically encodable fluorescent reporter. We show that THG imaging with an optimized point-spread function can reliably detect significant subcellular features of astrocytes, including cell nuclei, as well as the soma shape and boundaries.

Nonlinear-optical stain-free stereoimaging of astrocytes and gliovascular interfaces.

Methods of nonlinear optics provide a vast arsenal of tools for label-free brain imaging, offering a unique combination of chemical specificity, the ability to detect fine morphological features, and an unprecedentedly high, subdiffraction spatial resolution. While these techniques provide a rapidly growing platform for the microscopy of neurons and fine intraneural structures, optical imaging of astroglia still largely relies on filament-protein-antibody staining, subject to limitations and difficulties especially severe in live-brain studies. Once viewed as an ancillary, inert brain scaffold, astroglia are being promoted, as a part of an ongoing paradigm shift in neurosciences, into the role of a key active agent of intercellular communication and information processing, playing a significant role in brain functioning under normal and pathological conditions.

Kinetic-Spectrophotometric Determination of Thiocyanate in Human Saliva Based on Landolt Effect in Presence of Astrafloxine FF.

In the present study a kinetic-spectrophotometric method for thiocyanate determination is described. The suggested method for the determination of thiocyanate is based on its "Landolt effect" on the reaction of bromate with hydrobromic acid, which leads to the formation of only one halogen bromine. The reaction was monitored spectrophotometrically at the maximum wavelength of astrafloxine FF light absorption at 535 nm.

The whither of bacteriophytochrome-based near-infrared fluorescent proteins: Insights from two-photon absorption spectroscopy.

We present one- and two-photon-absorption fluorescence spectroscopic analysis of biliverdin (BV) chromophore-based single-domain near-infrared fluorescent proteins (iRFPs). The results of these studies are used to estimate the internal electric fields acting on BV inside iRFPs and quantify the electric dipole properties of this chromophore, defining the red shift of excitation and emission spectra of BV-based iRFPs. The iRFP studied in this work is shown to fit well the global diagram of the red-shift tunability of currently available BV-based iRFPs as dictated by the quadratic Stark effect, suggesting the existence of the lower bound for the strongest red shifts attainable within this family of fluorescent proteins.

Thermogenetic stimulation of single neocortical pyramidal neurons transfected with TRPV1-L channels.

Thermogenetics is a promising innovative neurostimulation technique, which enables robust activation of single neurons using thermosensitive cation channels and IR stimulation. The main advantage of IR stimulation compared to conventional visible light optogenetics is the depth of penetration (up to millimeters). Due to physiological limitations, thermogenetic molecular tools for mammalian brain stimulation remain poorly developed.

[Prevalence of chronic somatic diseases in workers engaged into luminescent lamps production].

The article presents results of epidemiologic study concerning occupational risk of chronic general somatic diseases in workers engaged into luminescent lamps production. Evidences are that hazardous work conditions affecting workers in main workshops of luminescent lamps production increase prevalence of chronic locomotory and connective tissue diseases, skin and cellular tissue disorders, respiratory diseases.

[Bacillus subtilis and streptomycin resistant mutant growth in the medium with saponite].

The influence of dispersed saponite on growth activity of Bacillus subtilis IMV B-7023 and its streptomycin resistant mutant has been shown. The effectiveness of this process depends on the content of dispersed material and phosphate in the medium. It has been found that when B.

[Special industrial medicine as a basis for workers' health preservation].

The article covers results and prospects of research in special industrial medicine on improving methodology of complex evaluation of work conditions in major economy branches including medical sphere workers. On the basis of ecologic epidemiologic research, remote effects of occupational and non-industrial hazards in workers and general population were studied, new technologic processes and equipment were assessed, principles for unifying methods to control chemicals in workplace air were defined, regulation methodical documents concordant with WHO, ILO and EC are specified.

[Problems of more healthy work conditions, occupational diseases prevention on enterprises of major economic branches].

The article deals with evaluation of contemporary work conditions in mining enterprises, iron industry, aluminium production plants. Work conditions are classified according to hazard level and jeopardy in various occupations within the enterprises. Reports presented by Russian Mining Metallurgy Trade-union on occupational morbidity over 2002-2010 were summarized.

[Contemporary work conditions and occupational morbidity in metallurgists].

Based on analysis of materials provided by Central Council of Russian Federal Coal Miners Trade Union, the authors assessed contemporary work conditions and occupational morbidity among workers engaged into iron industry. In these enterprises, a total of 68.4% of certified workplaces are assigned to hazardous and jeopardy class (3 and 4 degree of variable hazards).

[Influence of titanium dioxide on growth of Azotobacter vinelandii IMV V-7076].

Adding highly dispersed titanium dioxide particles of the culture medium has a stimulatory effect on growth of Azotobacter vinelandii. The maximum effect was observed when using 5 g/l and 10 g/l concentrations of this component. Under these conditions the number of grown bacteria is several times more than in the control variants.

[Characteristics of mine aerosol and occupational pulmonary diseases in highly-mechanized mine workers].

The article contains evaluation of physical and chemical properties of mine aerosol in mines using self-propelled diesel devices, information on the aerosol and exhaust gases components concentrations in the workplace air. Dispersed phase of the aerosol is presented by mineral and organic components, mineral and soot particles absorb gaseous exhaust components. Feature of occupational pulmonary diseases in highly-mechanized mine workers is toxic dust affection of bronchi, mostly with asthmatic course and chronic obstructive type of respiratory dysfunction, relatively short-term disease development.

[Work conditions and occupational morbidity in workers of aluminium production enterprises].

The article covers analysis of work conditions for aluminium plant workers, through workplaces certification. The authors specified work condition classes according to the jeopardy degree. Number of workplaces with conditions having occupational hazards' MAC and MAL excess 10-fold and over (class 3.

[Topical problems of occupational hygiene on extracting enterprises of Far North].

The article covers peculiarities of work conditions and their classification on enterprises extracting and processing raw materials in climate conditions of Far North, contains parameters of workers' morbidity.

Direct atomic absorption spectrometry determination of tin, lead, cadmium and zinc in high-purity graphite with flame furnace atomizer.

This work described methodology of Sn, Pb, Cd and Zn impurities determination in high-purity graphite at direct atomic absorption spectrometry (AAS) with flame furnace (FF) atomizer. It was evidence that quality of AAS measurements are depended from sample amount, its homogeneity, particle size, as well as calibration procedure and operation parameters of FF atomizer. Prior to analysis the method has been developed and optimized with respect to the furnace heating temperature and flame composition of FF atomizer.