Efficient generation of few-cycle pulses beyond 10 μm from an optical parametric amplifier pumped by a 1-µm laser system.

Nonlinear vibrational spectroscopy profits from broadband sources emitting in the molecular fingerprint region. Yet, broadband lasers operating at wavelengths above 7 μm have been lacking, while traditional cascaded parametric frequency down-conversion schemes suffer from exceedingly low conversion efficiencies. Here we present efficient, direct frequency down-conversion of femtosecond 100-kHz, 1.

Mathematical Description of the Increase in Selectivity of an Anion-Exchange Membrane Due to Its Modification with a Perfluorosulfonated Ionomer.

In this paper, we simulate the changes in the structure and transport properties of an anion-exchange membrane (CJMA-7, Hefei Chemjoy Polymer Materials Co. Ltd., China) caused by its modification with a perfluorosulfonated ionomer (PFSI).

Elastodynamic Behaviour of Laminate Structures with Soft Thin Interlayers: Theory and Experiment.

Laminate structures composed of stiff plates and thin soft interlayers are widely used in aerospace, automotive and civil engineering encouraging the development of reliable non-destructive strategies for their condition assessment. In the paper, elastodynamic behaviour of such laminate structures is investigated with emphasis on its application in ultrasonic based NDT and SHM for the identification of interlayer mechanical and interfacial contact properties. A particular attention is given to the practically important frequency range, in which the wavelength considerably exceeds the thickness of the film.

Mathematical Modeling of the Effect of Pulsed Electric Field Mode and Solution Flow Rate on Protein Fouling during Bipolar Membrane Electroacidificaiton of Caseinate Solution.

A one-dimensional non-stationary model was developed for a better understanding of the protein fouling formation mechanism during electroacidification of caseinate solution using electrodialysis with bipolar membranes (EDBM) in pulsed electric field (PEF) mode. Four different PEF modes were investigated with pulse-pause durations of 10-10 s, 10-20 s, 10-33 s, 10-50 s. For each current mode 3 different flow rates were considered, corresponding to Reynolds numbers, Re, equal to 187, 374 and 560.

Dependence of Electrochemical Properties of MK-40 Heterogeneous Membrane on Number of Adsorbed Layers of Polymers.

The creation of monovalent selective ion exchange membranes benefits the desalination of surface waters by removing interfering monovalent ions while preserving polyvalent ionic nutrients. Studies of a promising method of layer-by-layer adsorption of polymers for the creation of monovalent selective coatings note a significant effect of the number of formed layers and of the nature of the external layer on the properties of the resulting membranes. This article reports the changes in properties of layer-by-layer coated heterogeneous membranes occurring at increasing numbers of layers that are attributed to the supposed intermixing of polymers between the layers, namely dependence of limiting current densities determined from i-V curve, enhanced electroconvection that was attributed to the appearing electrical heterogeneity of the surface, and the decreasing monovalent selectivity in electrodialysis of mixed NaCl + CaCl solution (from 1.

Experimental and Theoretical Study of an Autowave Process in a Magnetic Fluid.

Magnetic fluid (MF) is a colloidal system consisting of ferromagnetic particles (magnetite) with a diameter of ~10 nm suspended in a dispersion medium of a carrier fluid (for example, kerosene). A distinctive feature of magnetic fluid is the fact that when an electric field is applied to it using two electrodes, thin layers consisting of close-packed particles of the dispersed phase are formed in the regions near the surface of both electrodes. These layers significantly affect the macroscopic properties of the colloidal system.

Features of the Preparation and Luminescence of Langmuir-Blodgett Films Based on the Tb(III) Complex with 3-Methyl-1-phenyl-4-stearoylpyrazol-5-one and 2,2'-Bipyridine.

In this study, we investigated the effect of terbium ions (Tb on the subphases of the limiting area of the molecule for the complex compound (CC) TbL∙bipy (where HL is 3-methyl-1-phenyl-4-stearoylpyrazol-5-one and bipy is 2,2'-bipyridine). We examined the Langmuir monolayer and the change in the luminescence properties of TbL∙bipy-based Langmuir-Blodgett films (LBFs). The analysis of the compression isotherms, infrared, and luminescence spectra of TbL∙bipy LBFs was performed by varying the concentration of Tb in the subphases.

[Results of reconstructive surgery with formation of low colorectal anastomoses after previous Hartmann's procedure].

Objective: To evaluate the efficacy and safety of original access to short rectal stump compared to traditional direct one.

Material And Methods: A retrospective-prospective cohort comparative study was conducted between 2012 and 2018. Inclusion criterion was previous Hartmann's procedure with formation of a short rectal stump.

Modeling Asymmetry of a Current-Voltage Curve of a Novel MF-4SC/PTMSP Bilayer Membrane.

A novel bilayer cation-exchange membrane-consisting of a thick layer of a pristine perfluorinated membrane MF-4SC (Russian equivalent of Nafion-117) and a thinner layer (1 μm) of the membrane, on a base of glassy polymer of internal microporosity poly(1-trimethylsilyl-1-propyne) (PTMSP)-was prepared and characterized. Using the physicochemical characteristics of one-layer membranes MF-4SC and PTMSP in 0.05 M HCl and NaCl solutions, the asymmetric current-voltage curves (CVC) of the bilayer composite were described with good accuracy up to the overlimiting regime, based on the "fine-porous membrane" model.

Reduction of Deuterium Level Supports Resistance of Neurons to Glucose Deprivation and Hypoxia: Study in Cultures of Neurons and on Animals.

The effect of a reduced deuterium (D) content in the incubation medium on the survival of cultured neurons in vitro and under glucose deprivation was studied. In addition, we studied the effect of a decrease in the deuterium content in the rat brain on oxidative processes in the nervous tissue, its antioxidant protection, and training of rats in the T-shaped maze test under hypoxic conditions. For experiments with cultures of neurons, 7-8-day cultures of cerebellar neurons were used.

Gas-Transport Characteristics of PdCu-Nb-PdCu Membranes Modified with Nanostructured Palladium Coating.

A method for obtaining composite gas-diffusion PdCu-Nb-PdCu membranes modified with a nanostructured crystalline coating was developed to increase the performance of Nb-based membranes. A modifying functional layer with a controlled size and composition was synthesized by electrochemical deposition, which made it possible to determine a certain geometric shape for palladium nanocrystallites. Developed PdCu-Nb-PdCu membranes have demonstrated flux values up to 0.

Influence of Electroconvection on Chronopotentiograms of an Anion-Exchange Membrane in Solutions of Weak Polybasic Acid Salts.

Visualization of electroconvective (EC) vortices at the undulated surface of an AMX anion-exchange membrane (Astom, Osaka, Japan) was carried out in parallel with the measurement of chronopotentiograms. Weak polybasic acid salts, including 0.02 M solutions of tartaric (NaHT), phosphoric (NaHPO), and citric (NaHCit) acids salts, and NaCl were investigated.

Removal of Excess Alkali from Sodium Naphthenate Solution by Electrodialysis Using Bilayer Membranes for Subsequent Conversion to Naphthenic Acids.

The processing of solutions containing sodium salts of naphthenic acids (sodium naphthenate) is in high demand due to the high value of the latter. Such solutions usually include an excessive amount of alkali and a pH of around 13. Bipolar electrodialysis can convert sodium naphthenates into naphthenic acids; however, until pH 6.

In-Depth on the Fouling and Antifouling of Ion-Exchange Membranes.

This work is a synthesis of several in-depth studies on fouling and antifouling phenomena of ion-exchange membranes (IEMs) [...

,'-Diphenyldithiomalonodiamide: Structural Features, Acidic Properties, and In Silico Estimation of Biological Activity.

The spectral characteristics of dithiomalondianilide (,'-diphenyldithiomalonodiamide) were studied, and the dissociation constant was determined by potentiometric titration. Quantum-chemical methods at the B3LYP-D3BJ/6-311+G (2d,p) level were used to calculate the molecular geometry and vibrational spectra of the most stable tautomeric forms of dithiomalondianilide. The bioavailability parameters were calculated, and possible protein targets were predicted by the protein ligand docking method.

2-Amino-4,5-dihydrothiophene-3-carbonitriles: A New Synthesis, Quantum Chemical Studies, and Mannich-Type Reactions Leading to New Hexahydrothieno[2,3-d]pyrimidines.

-2-Amino-4-aryl-5-benzoyl-4,5-dihydrothiophene-3-carbonitriles were prepared either by the reaction of 3-aryl-2-cyanothioacrylamides with α-thiocyanatoacetophenone or by the Michael-type addition of cyanothioacetamide to α-bromochalcones followed by intramolecular cyclization. The mechanism of the first reaction was studied using high-level quantum chemical calculations. Density functional theory (DFT) studies were carried out to determine the mechanism of the first reaction.

Mathematical Modeling of the Phenomenon of Space-Charge Breakdown in the Galvanostatic Mode in the Section of the Electromembrane Desalination Channel.

One of the ways to increase the efficiency of the desalination process in membrane systems is to use intensive current modes. Recently, the phenomenon of space-charge breakdown was theoretically described for desalination under intensive current modes. The space-charge breakdown is a decrease in the magnitude and size of the extended space charge regions (SCRs) of opposite signs, formed at the cation- and anion-exchange membranes in the desalination channel, when they approach each other.

Ion-Exchange Membranes and Processes (Volume II).

Ion exchange membranes (IEMs) and related processes have generated increased interest among researchers in the last few years, according to the analysis of publication activity in Scopus [...

Ion-Exchange Membranes and Processes.

Synthetic ion exchange membranes (IEMs) are made from organic, inorganic, or mixed and composite materials [...

A Review on Ion-Exchange Membranes Fouling during Electrodialysis Process in Food Industry, Part 2: Influence on Transport Properties and Electrochemical Characteristics, Cleaning and Its Consequences.

Ion-exchange membranes (IEMs) are increasingly used in dialysis and electrodialysis processes for the extraction, fractionation and concentration of valuable components, as well as reagent-free control of liquid media pH in the food industry. Fouling of IEMs is specific compared to that observed in the case of reverse or direct osmosis, ultrafiltration, microfiltration, and other membrane processes. This specificity is determined by the high concentration of fixed groups in IEMs, as well as by the phenomena inherent only in electromembrane processes, i.

Influence of Environmental Parameters on the Stability of the DNA Molecule.

Fluctuations in viscosity within the cell nucleus have wide limits. When a DNA molecule passes from the region of high viscosity values to the region of low values, open states, denaturation bubbles, and unweaving of DNA strands can occur. Stabilization of the molecule is provided by energy dissipation-dissipation due to interaction with the environment.

Accessing Perfluoroaryl Sulfonimidamides and Sulfoximines via Photogenerated Perfluoroaryl Nitrenes: Synthesis and Application as a Chiral Auxiliary.

Sulfonimidamides (SIAs) and sulfoximines (SOIs) have attracted attention due to their potential in agriculture and in medicinal chemistry as bioisosteres of biologically active compounds, and new synthetic methods are needed to access and explore these compounds. Herein, we present a light-promoted generation of perfluorinated aromatic nitrenes, from perfluorinated azides, that subsequently are allowed to react with sulfinamides and sulfoxides, generating achiral and chiral SIAs and SOIs. One of the enantiopure SIAs was evaluated as a novel chiral auxiliary in Grignard additions to the imines yielding the product in up to 96:4 diastereomeric ratio.

A Review on Ion-Exchange Membrane Fouling during the Electrodialysis Process in the Food Industry, Part 1: Types, Effects, Characterization Methods, Fouling Mechanisms and Interactions.

Electrodialysis (ED) was first established for water desalination and is still highly recommended in this field for its high water recovery, long lifetime and acceptable electricity consumption. Today, thanks to technological progress in ED processes and the emergence of new ion-exchange membranes (IEMs), ED has been extended to many other applications in the food industry. This expansion of uses has also generated several problems such as IEMs' lifetime limitation due to different ageing phenomena (because of organic and/or mineral compounds).

Cytoprotective and Antioxidant Effects of Meconic Acid in Model Systems.

We studied the antioxidant and cytoprotective effects of meconic acid in the model systems. Meconic acid, similar to commercial drug Mexidol, reduced the intensity of chemiluminescence in the model system of yolk lipoproteins. Meconic acid also reduced the toxic effect of glutamate on neurons in the primary cerebellar culture, but had no effect on cell viability under normal conditions.