Soliton based χ(2) combs in high-Q optical microresonators.

Investigations of the frequency combs in χ(3) microresonators have passed a critical point when the soliton based regimes are well established and realized on different platforms. For χ(2) microresonators, where the first harmonic (FH) and second harmonic (SH) envelopes are coupled via the SH generation and optical parametric oscillation, the comb-soliton studies are just starting. Here we report on a vast accessible dual χ(2) soliton-comb family in high-Q microresonators with the SH and FH combs centered at the pump frequency ωp and its half ωp/2. Vicinity of the point of equal FH and SH group velocities λc, available via proper radial poling, is found to be the most advantageous for the generation of spectrally broad dual FH-SH combs. Our predictions as applied to lithium niobate resonators include the dependence of comb and dissipative soliton parameters on the pump power, the deviation λp - λc, the modal quality factors and frequency detunings, and the necessary parameters of radial poling of the resonator. These predictions form a solid basis for the realization of χ(2) frequency combs.

[Selenium content in gluten-free products].

Special diets are used for the treatment and prevention of diseases of the digestive system, taking into account individual food intolerance and possible allergic reactions. The monotony of the diet due to the limited range of recommended foods and dishes negatively affects both the effectiveness of the treatment of gluten intolerance, and the provision of the body with essential and replaceable nutrients. The aim of this study was to determine the selenium content in the flour of gluten-free crops (rice, corn, buckwheat and amaranth), their mixtures, as well as in dishes (pancakes) from a mixture of amaranth and buckwheat flours. Material and methods. The following raw materials were used in the study: amaranth flour, unboiled buckwheat groats, whole grain rice flour and corn flour. By mixing the components in a laboratory mixer, dry gluten-free compositions were obtained: a mixture of amaranth flour and flour from native buckwheat; a mixture of amaranth and rice flour and a mixture of amaranth and corn flour in the ratio of 1:2 and 1:1; and a mixture of amaranth, buckwheat and corn flour in equal proportions. In laboratory baking of pancakes, mixtures of amaranth flour and flour from native buckwheat were used. The selenium content was determined by atomic absorption spectroscopy with electrothermal atomization after wet mineralization of the samples. Results. The results of the study showed that amaranth, buckwheat and corn are rich sources of selenium. The most valuable source of selenium was amaranth flour (515 µg/kg). Selenium content in native buckwheat flour and corn flour was 405 and 458 µg/kg, respectively. The lowest selenium content among the studied crops was found in rice flour (135 µg/kg). Selenium content in flour mixtures of the studied cultures ranged from 258 to 522 µg/kg. The highest values of selenium content were observed in mixtures of amaranth with corn flour (516-522 µg/kg). The lowest content of this trace element was found in mixtures containing rice flour (from 258 to 325 µg/kg). Selenium content in pancakes made from mixtures of amaranth flour and native buckwheat flour varied from 290 to 326 µg/kg. The calculation showed that the consumption of a portion of pancakes (50 g) by school-age children will satisfy their daily requirement for selenium by 7.3-8.1%. Conclusion. Regular inclusion of amaranth-based foods in the diet of children with gluten intolerance can positively affect the elimination of selenium deficiency.

Walk-off controlled self-starting frequency combs in χ(2) optical microresonators.

Investigations of frequency combs in χ(3) optical microresonators are burgeoning nowadays. Changeover to χ(2) resonators promises further advances and brings new challenges. Here, the comb generation entails not only coupled first and second harmonics (FHs and SHs) and two dispersion coefficients but also a substantial difference in the group velocities - the temporal walk-off. We predict walk-off controlled highly stable comb generation, which is drastically different from that known in the χ(3) case. This includes the general notion of antiperiodic states; formation of localized coherent antiperiodic steady states (solitons), where the FH and SH envelopes move with a common velocity without shape changes; characterization of a new vast family of antiperiodic solitons; and the dependence of comb spectra on the pump power and the group velocity difference.

[THE CELLULAR COMPOSITION OF THE EPITHELIUM OF THE VILLUS OF THE MUCOUS MEMBRANE OF THE DUODENUM OF RATS IN THE CONDITIONS OF EPICHLOROHYDRIN AND DRUG INFLUENCE].

Purpose of the research is to study the nature of the disorders of the villi of the duodenal mucous membrane (MM) in conditions of long-acting ECH as well as to substantiate experimentally the effectiveness of the use of the extract of Echinacea purpurea (EP) and thiotriazoline for the purpose of these disorders correction. The withdrawal of the rats from the experiment was carried out on the 1st, 7th, 15th, 30th and 60th day after the completion of the administration of ECH, EP extract and thiotriazoline. Histological processing of duodenum fragments was performed according to the standard method. The cell composition of the villus epithelium of duodenal MM was evaluated using a laboratory microscope of the MC 100 (Micros, Austria) and the Microvisible software (version 1.11.10). The determination of the significance of differences was carried out according to the Mann-Whitney U criterion. Differences were considered significant at p<0.05. Prolonged action of ECH led to a decrease in the number of cells in one villus of duodenal MM. This decrease persisted after the end of the administration of this chemical. There was a decrease in the number of columnar epithelial cells, goblet exocrinocytes and argyrophil endocrinocytes. In rats that did not receive ECH, administration of an EP extract was accompanied by a short-term increase in the number of columnar epithelial cells in one villus of duodenal MM. The administration of thiotriazolin to rats that did not receive ECH caused a short-term increase in the number of cells in one villus of duodenal MM and the number of columnar epithelial cells in the one villus of duodenal MM. The use of EP extract on the background of inhalations of ECH reduced the degree of decrease in the number of cells in one villus of duodenal MM and the number of columnar epitheliocytes in one villus of duodenal MM, reduced the degree and duration of reduction in the number of goblet exocrinocytes in one villus of duodenal MM, reduced the duration of reduction in the number of argyrophil endocrinocytes in one villus of duodenal MM. The use of thiotriazolin during the administration of ECH led to a decrease in the degree and duration of a decrease in the number of cells in one villus of duodenal MM and the number of columnar epithelial cells in one villus of duodenal MM, and also prevented the occurrence of a decrease in the number of goblet exocrinocytes and argyrophil endocrinocytes in one villus of duodenal MM.

Self-Induced Faraday Instability Laser.

We predict the onset of self-induced parametric or Faraday instabilities in a laser, spontaneously caused by the presence of pump depletion, which leads to a periodic gain landscape for light propagating in the cavity. As a result of the instability, continuous wave oscillation becomes unstable even in the normal dispersion regime of the cavity, and a periodic train of pulses with ultrahigh repetition rate is generated. Application to the case of Raman fiber lasers is described, in good quantitative agreement between our conceptual analysis and numerical modeling.

Generation of spatio-temporal extreme events in noise-like pulses NPE mode-locked fibre laser.

We experimentally study spatio-temporal generation of extreme events in the radiation of NPE mode-locked fibre laser generating noise-like pulses. We show that new pulses starts from high-intensity spatio-temporal structure which consist of mainly 3 subsequent pulses which are both separated over fast and slow evolution time. Statistical analysis of the noise-like pulse evolution over round-trips shows that the pulse width and intensity varies with a period of around 85 round-trips which does not change from pulse to pulse. The intensity probability density function has a heavy tail originated only from events of pulse formation.

Secure polarization-independent subcarrier quantum key distribution in optical fiber channel using BB84 protocol with a strong reference.

A quantum key distribution system based on the subcarrier wave modulation method has been demonstrated which employs the BB84 protocol with a strong reference to generate secure bits at a rate of 16.5 kbit/s with an error of 0.5% over an optical channel of 10 dB loss, and 18 bits/s with an error of 0.75% over 25 dB of channel loss. To the best of our knowledge, these results represent the highest channel loss reported for secure quantum key distribution using the subcarrier wave approach. A passive unidirectional scheme has been used to compensate for the polarization dependence of the phase modulators in the receiver module, which resulted in a high visibility of 98.8%. The system is thus fully insensitive to polarization fluctuations and robust to environmental changes, making the approach promising for use in optical telecommunication networks. Further improvements in secure key rate and transmission distance can be achieved by implementing the decoy states protocol or by optimizing the mean photon number used in line with experimental parameters.

Raman and nuclear magnetic resonance investigation of alkali metal vapor interaction with alkene-based anti-relaxation coating.

The use of anti-relaxation coatings in alkali vapor cells yields substantial performance improvements compared to a bare glass surface by reducing the probability of spin relaxation in wall collisions by several orders of magnitude. Some of the most effective anti-relaxation coating materials are alpha-olefins, which (as in the case of more traditional paraffin coatings) must undergo a curing period after cell manufacturing in order to achieve the desired behavior. Until now, however, it has been unclear what physicochemical processes occur during cell curing, and how they may affect relevant cell properties. We present the results of nondestructive Raman-spectroscopy and magnetic-resonance investigations of the influence of alkali metal vapor (Cs or K) on an alpha-olefin, 1-nonadecene coating the inner surface of a glass cell. It was found that during the curing process, the alkali metal catalyzes migration of the carbon-carbon double bond, yielding a mixture of cis- and trans-2-nonadecene.

INFLUENCE OF INFLUENZA A VIRUS AND BACTERIAL LIPOPOLYSACCHARIDE ON PROLIFERATION AND GENE EXPRESSION OF CYTOKINES AND OTHER CELLULAR FACTORS IN CELLS OF ESTABLISHED ENDOTHELIAL CELL LINE ECV-304.

Change of state of endothelial cells occurs under the action of viral infection and bacterial lipopolysaccharide (LPS) that leads to cell dysfunction. Therefore, the aim of the current study was to investigate the effect of LPS from Escherichia coli and influenza A virus on proliferative activity of human endothelial cells (ECV-304) and gene expression of several cytokines and cellular factors: TNFá, TGFâ, IFN-ã, MMP-9, NF-êB, Rho A, eNOS and iNOS. It was found that ECV-304 cells once infected with very low infectious doses of influenza virus acquire the ability to long-term active proliferation (over 8 passages). Addition of LPS E. coli reduced the virus-stimulated cell proliferation. It was shown that influenza virus and LPS can affect on gene expression of cytokine and other cellular factors. When endothelial cells had been infected with influenza A virus in the presence of LPS, there was a significant increase in the expression of several genes and replacement of some genes expression on the expression of other genes. Expression of MMP-9 gene was inhibited in the case of separate exposure to the virus and LPS, but it was significantly increased during the first day under the adding of the virus and LPS together, as well as the activity of the IFN-ã gene; gene of TNFá was active for only 1­3 days whereas genes expression of other factors (TGFâ, eNOS, iNOS, NF-êB and Rho A) increased significantly at the 5th day as in the case of adding only LPS. Thus, the change of physiological state of endothelial cells occurs in the presence of influenza A virus and LPS and it can be caused during different time periods (as well as by varying degrees of virus infection of cells) by different cellular factors and possibly with involvement of different signaling pathways.

Linear compression of chirped pulses in optical fibre with large step-index mode area.

The possibilities and limitations of linear compression of positively chirped pulses in the negative-dispersion region of a step-index large mode-area single-mode optical fibre are investigated for the first time. Analytical formulae for critical values of radiation power are found, below which pedestal-free pulse compression is possible down to the Fourier limit. It is demonstrated that at radiation powers exceeding these critical values, there exists an optimal compressing fibre length, over which laser pulses reach the minimum of the time-bandwidth product, and beyond which irreversible pulse deformation occurs. The modelling results agree well with the experimental data.

[Influence of Different Type of Surfactant on Bacteriolytic Activity of Lysozyme].

The influence ofvarious surfactants (anionic sodium dodecyl sulfate, SDS, cationic dodecyltrimethylarnmonium bromide, DTAB, and zwitterionic cocoamidopropylbetaine, CAPB) on the activity of the chicken egg lysozyme is investigated. Lysis of Gram-positive bacteria by the enzyme was carried out at pH 7.2 and ionic strength of 0.15 M. It was found that at low SDS and DTAB concentrations (less than 1 x 10(-5) M) the bacteriolytic activity increases by 30-140%. At higher concentrations (1 x 10(-5) - 1 x 10(4) M) the activity returns to the level observed in the absence of the surfactants. The elevated activity correlated with the formation of hydrophobic lysozyme-surfactant complexes. Introduction of CAPB at concentrations above 1 x 10(-5) M sig, nificantly diminished the bacteriolytic activity due to CAPB induced aggregation of lysozyme.

[Ontogenetic Mechanisms of Explosive Morphological Divergence in the Lake Tana (Ethiopia) Species Flock of Large African Barbs (Labeobarbus; Cyprinidae; Teleostei)].

Species flock of Lake Tana (Ethiopia) large African barbs (Labeobarbus; Cyprinidae; Teleostei) was studied as a model system for investigating ontogenetic mechanisms of the explosive morphological divergence often accompanying sympatric speciation in bony fishes. Comparative morphological analysis carried out with the use ofgeometric morphometric techniques revealed quantitative differences in the head shapes of species under study. Comparative analysis of skull development revealed significant interspecies differences in the temporal characteristics of craniogenesis in these species. These two lines of evidence suggest that heterochronies in craniogenesis underlie divergence in the head shapes of adult Tana barbs. This prediction was verified via experimental changes of temporal characteristics of craniogenesis in L. intermedius, a putative ancestor for the Lake Tana species flock. For this aim, timing and rate of skull development were changed by artificial manipulation of thyroid hormone levels. In sum, it was shown that it is heterochronies that underlie an explosive morphological divergence of the Lake Tana barbs species flock. Our findings together with those reported in the literature suggest variability in the activity of the hypothalamic-pituitary-thyroid axis to contribute to these heterochronies.

[Correlation between biochemical parameters of oxidative stress, endogenous intoxication and regulation of vascular tone in patients with burn injury].

Burn injury is accompanied by the formation of reactive oxygen species (ROS). Excessive production of ROS results in oxidative stress. Peroxidation damage of proteins causes their degradation and the formation of toxic fragments con- tributing to the development of endogenous intoxication. Furthermore, burns cause pronounced inflammatory reaction in the lesion site leading to poor circulation. The purpose of this study was an investigation of relationship between disturbances in the prooxidant/antioxidant system, severity of endogenous intoxication and disturbances of endogenous vascular regulation to assess the severity and prognosis of complications in patients with burn injury. 26 patients with- burn injury were investigated; they were divided into 2 groups according to the severity of injury on the basis of Frank index (FI): group 1--FI < 60 CU and group 2--FI ≥ 60 CU. The investigation of blood serum was performed on 1-3, 7, 14, 21 and 28 day after burn injury. Malondialdehyde (MDA), total antioxidant status (TAS), the level of middle weight molecules, stable metabolites of nitric oxide (NOx) and angiotensin-converting enzyme (ACE) activity were determined in the serum. Significant increase of MDA level, decrease of TAS and NOx level were found in two groups of patients throughout the observation period. We also found a disturbance in coupled interaction of NO and ACE. These data point to the development of oxidative stress and imbalance in endogenous regulation of vascular tone. There was a trend toward more pronounced oxidative stress in group 2. Significant correlations between parameters of oxidative stress, endogenous intoxication, endogenous factors of vascular regulation, depth of burn injury and FI were obtained in two groups. MDA, TAS can serve as one of the prognostic markers of condition severity of burned patients and therapy adequacy.

High average power mode-locked figure-eight Yb fibre master oscillator.

For the first time, we demonstrate the possibility to generate record-high output radiation power exceeding 1 W in an all-fibre figure-eight mode-locked Yb fibre master oscillator based on non-linear amplifying loop mirror. Generated at the repetition rate of 25 MHz clusters of sub-pulses with duration of no more than 200 fs have envelope width of 23 ps or less. Two typical mode-locked laser regimes with substantially different generation spectra are identified and results of their study presented. Numerical modelling of laser generation in the proposed layout agrees well with the measured experimental data.

Experimental substantiation and clinical use of a combination of dermal matrix with allogenic or autologous cells for the treatment of extensive traumatic wounds.

We carried out a comparative experimental and clinical study of the efficiency of the combination of dermal matrix with autologous and allogenic cells for creation of an optimal biological wound coating. Experiments on outbred mice have demonstrated that the use of dermal matrix in combination with allogeneic or autologous cells shortens the inflammation phase and accelerated maturation of the granulation tissue. Clinical application of biological wound dressing based on dermal matrix in combination with autologous or allogeneic mesenchymal multipotent stromal cells prevented septic complications and shortened the time of preparing extensive traumatic wounds with skin defect to autodermoplasty.

Thyroid hormones in the skeletogenesis and accessory sources of endogenous hormones in Xenopus laevis (Amphibia; Anura) ontogeny: Experimental evidence.

Skeletal development was studied in normal and goitrogen-treated Xenopus laevis tadpoles reared under thyroid hormone (TH) deficiency. Early stages of skeletal development proceed similarly in both groups. Later stages are retarded or completely arrested in goitrogen-treated tadpoles. After goitrogen-treated tadpoles were transferred into pure water or into a medium containing both goitrogen and exogenous TH, tadpoles resumed development. Consequently, late stages of skeletogenesis are TH-dependent and TH-induced. Athyroid X. laevis "giant tadpoles" described in literature differ from goitrogen-arrested tadpoles in that they have features which require TH to appear. The appearance of TH-depended features in giant tadpoles indicates the occurrence of the additional sources of TH other than thyroid gland.

Generation dynamics of the narrowband Yb-doped fiber laser.

We present direct real-time experimental measurements and numerical modeling of temporal and statistical properties for the Ytterbium-doped fiber laser with spectral bandwidth of ~2 GHz. The obtained results demonstrate nearly exponential probability density function for intensity fluctuations. A significant decrease below the Gaussian probability has been experimentally observed for intensity fluctuations having value more than 2.5 of average intensity that may be treated as indication of some mode correlations.

Surface modification of graphene nanopores for protein translocation.

Studies of DNA translocation through graphene nanopores have revealed their potential for DNA sequencing. Here we report a study of protein translocation through chemically modified graphene nanopores. A transmission electron microscope (TEM) was used to cut nanopores with diameters between 5 and 20 nm in multilayer graphene prepared by chemical vapor deposition (CVD). After oxygen plasma treatment, the dependence of the measured ionic current on salt concentration and pH was consistent with a small surface charge induced by the formation of carboxyl groups. While translocation of gold nanoparticles (10 nm) was readily detected through such treated pores of a larger diameter, translocation of the protein ferritin was not observed either for oxygen plasma treated pores, or for pores modified with mercaptohexadecanoic acid. Ferritin translocation events were reliably observed after the pores were modified with the phospholipid-PEG (DPPE-PEG750) amphiphile. The ion current signature of translocation events was complex, suggesting that a series of interactions between the protein and pores occurs during the process.

[Novel NADPH-dependent L-aspartate dehydrogenases from the mesophilic nitrogen-fixing bacteria Rhodopseudomonas palustris and Bradyrhizobium japonicum].

The genes encoding putative L-aspartate dehydrogenases (EC 1.4.1.21, ADH) from the mesophilic nitrogen-fixing bacteria Rhodopseudomonas palustris and Bradyrhizobium japonicum were cloned and expressed in Escherichia coli. The respective enzymes in the form of hybrid proteins with N-terminal hexahistidine tags were purified to apparent homogeneity. Both enzymes catalyzed in vitro the reductive amination of oxaloacetate to L-aspartate by an order faster than the reverse reaction at a respective pH optimum of 8.0-9.0 and 9.8; also, the enzymes only catalyzed amination under physiological conditions (pH 7.0-8.0). Their specificity to NADPH was higher by 1-2 orders of magnitude than that to NADH. The apparent KM values of ADHs from R. palustris for oxaloacetate, ammonium, and NADPH at pH 9.0 were 9.2, 11.3, and 0.21 mM, respectively, and the corresponding KM values of ADH from B. japonicum were 21, 4.3, and 0.032 mM, respectively. The amination activity of novel ADHs may be important for the fixation of inorganic nitrogen in vivo and used for the construction of a bacterial strain-producer of L-aspartate by metabolic engineering methods.

[Stepwise treatment in patients with isolated thermal inhalation injury].

AIM: To evaluate the efficiency of stepwise treatment in patients with isolated thermal inhalation injury (TIJ). SUBJECTS AND METHODS: The study enrolled 101 patients with isolated TIJ. A study group (n=56) was treated at the Pulmonology Department after managing at the Burn Center (BC); a control group (n=45) received no systematic treatment after discharging from BC. The magnitude of respiratory symptoms (according to the rating system) and external respiratory function (ERF) was evaluated and fibrobronchoscopy was made in all the included patients at their discharge from BC. On admission to the Pulmonology Department, the study group patients underwent evaluation of the magnitude of respiratory symptoms, EFR, and lung diffusing capacity, determination of blood gas composition and exercise tolerance, and chest computed tomography. Respiratory symptoms, ERF, and exercise tolerance were evaluated in all the included patients one month after hospital discharge. RESULTS: Examination at the Pulmonology Department established preserved respiratory manifestations in patients who had to continue therapy. The use of beta2-agonists or inhaled steroids used in combination or alone need, mucoregulators or antibiotics revealed the efficiency of a stepwise approach to managing patients with TIJ. CONCLUSION: There is evidence that it is expedient to perform two-stage treatment in patients with TIJ, by transferring them from BC to a specialized pulmonology hospital, which substantially enhances the efficiency of medical care for this contingent of patients.