Chirp-driven control over fast-slow light effects in epsilon-near-zero metamaterials.

Optical applications based on fast and slow light effects force the usage of metamaterials famous for their flexible dispersion properties. In this work, we apply the unique optical nonlocality of metal nanorod-based epsilon-near-zero (ENZ) metamaterials along with the chirp of femtosecond laser pulses for astonishing control of these effects. We demonstrate the switching between the fast and slow light phenomena via the change of the angle of incidence and/or the central wavelength of chirped pulses in the vicinity of metamaterial zero-transmission regime mediated by the ENZ nonlocality. We elucidate that the laser chirp allows one to manipulate and enhance the fast-slow light phenomena.

[Strictureplasty or resection? Optimal approach for fibrostenotic Crohn's disease]. / Strikturoplastika ili rezektsiya? Optimal'naya taktika pri fibrostenoticheskoi forme bolezni Krona.

The indications for surgical intervention in patients with Crohn's disease (CD) are ineffective therapy and complications of this disease. In case of fibrostenotic CD, strictureplasty or bowel resection are indicated. The indications for organ-sparing surgeries are multiple small bowel lesions, previous surgery for CD and short bowel syndrome. Strictureplasty is not advisable in patients with fistulas, abscesses, bowel perforation and severe hypoalbuminemia due to extremely high risk of anastomotic leakage. Therefore, bowel resection is recommended if strict indications for various types of strictureplasty are absent. This approach is associated with effective maintenance of remission and longer recurrence-free period.

Self-action effects in hyperbolic metamaterials based on gold nanorods.

Intensive studies of hyperbolic metamaterials (HMMs) are induced by unique optical properties of this type of artificial media associated with their hyperbolic dispersion. Special attention is attracted to the nonlinear optical response of HMMs, which reveals anomalous behavior in definite spectral regions. Third-order nonlinear optical self-action effects that are perspective for applications were analyzed numerically, whereas such experiments have not been performed up to now. In this work we study experimentally the effects of the nonlinear absorption and refraction in ordered arrays of gold nanorods in porous aluminum oxide. We demonstrate strong enhancement and sign reversal of these effects in the vicinity of the epsilon-near-zero spectral point due to the resonant light localization and transition from elliptical to hyperbolic dispersion regimes.

Viability of Bacteriophages in the Complex Hydrogel Wound Dressings in vitro.

Using bacteriophages to overcome the increasing resistance of microorganisms to antibiotics is a novel research venue of clinical importance. Among other challenges, this technique is expected to create and maintain an adequate local concentration of bacteriophages at the site of application. In addition, the possibility of combining the phage preparation with antioxidants and anesthetics may provide new options for stimulating the reparative process. The aim of the study was to assess the viability and lytic activity of bacteriophages incorporated into a hydrogel-based wound dressing that contains polyvinyl alcohol, phosphate buffer, with optional additions of succinic acid and lidocaine. Materials and Methods: A technique for incorporating bacteriophages into the complex hydrogel wound dressing ex tempore has been proposed. The bacteriolytic activity of phages inside the hydrogel was determined using standard microbiological techniques. Specifically, we used nutrient media with lawn cultures of Staphylococcus aureus added with the following antibacterial combinations: bacteriophages + succinic acid, bacteriophages + lidocaine, and bacteriophages + succinic acid + lidocaine. The lytic activity of bacteriophages was assessed within 1 to 7 days after the formation of the hydrogel. Results: In all samples containing bacteriophages, the presence of viable and lytically active phages was noted within 1 to 7 days, as evidenced by the "negative colonies" on the culture lawns. On days 1 to 3, no secondary growth was recorded in the phage-containing samples. In hydrogel samples containing phages, succinic acid, and lidocaine, secondary bacterial colonies were detected starting from day 4 indicating some reduction in the lytic activity. Conclusion: The results suggest that bacteriophages immobilized in the hydrogel maintain their viability and lytic activity, and this activity persists when the phages are combined with succinic acid and lidocaine.

Superluminal and slow femtosecond laser pulses in hyperbolic metamaterials in epsilon-near-zero regime.

Flourish of optics of hyperbolic metamaterials (HMMs) is stimulated by their exotic optical properties. Here, we demonstrate resonant changes of the group retardation and superluminal-like propagation of femtosecond laser pulses in nanorod-based HMMs in the vicinity of epsilon-near-zero spectral point responsible for the transition between topologically distinct elliptic and hyperbolic light dispersions. Resonant dynamics of ultrashort pulses appears in a unique case when their spectral components are in both dispersion regimes simultaneously. Our findings suggest HMMs as a powerful platform for future ultrafast photonics and are pivotal for growing nonlinear optics of hyperbolic media.

Second-harmonic generation spectroscopy in gold nanorod-based epsilon-near-zero metamaterials.

The interest in hyperbolic metamaterials is fueled by fascinating optical properties exhibited by this class of artificial media. Their optical features originate from hyperbolic dispersion emerging due to the shape anisotropy of the metal-dielectric composite. In this work, we study experimentally and numerically the second-harmonic generation (SHG) in ordered arrays of Au nanorods embedded in porous aluminum oxide. Strong increase of the SHG intensity in the vicinity of the epsilon-near-zero (ENZ) spectral point accompanied by dramatic phase modulation of the SHG wave is revealed. These effects are attributed to resonant enhancement of the electric field of the light wave and transition from the elliptical to hyperbolic dispersion law in hyperbolic metamaterials near the ENZ point.

Anomalous birefringence and enhanced magneto-optical effects in epsilon-near-zero metamaterials based on nanorods' arrays.

Hyperbolic metamaterials based on the ordered arrays of metal nanorods in a dielectric media are of great interest owing to new optical effects appearing in such artificial media. Here we study the effects in the polarization state of light passing through a nanocomposite material consisting of Au nanorods in porous alumina and a similar structure supplemented by a nanolayer of ferromagnetic nickel. We demonstrate that close to the epsilon-near-zero dispersion point, under the transition to the hyperbolic dispersion region, the nanocomposites reveal anomalously high modulation of the polarization state of light, which appears as polarization plane rotation and ellipticity changes of probing radiation with a zero ellipticity. This effect is applied for the giant enhancement of the Faraday effect in a continuous ferromagnetic film staying in contact with hyperbolic material. These findings open a path for the design of polarization state control by using hyperbolic metamaterials.

Magneto-optical effects in hyperbolic metamaterials.

Highly anisotropic metal-dielectric structures reveal unique dispersion properties providing new optical effects. Here we study experimentally linear optical and magneto-optical response of arrays of plasmonic gold nanorods and similar structures complemented by a thin nickel film. We show that both types of structures reveal distinct optical features expected for hyperbolic media and associated with the epsilon-near-zero (ENZ) and epsilon-near-pole (ENP) points. In the case of Ni-containing nanocomposites, we observe linear magneto-optical effects in transmission through the structure, increasing in the vicinity of these points. This observation reveals an important role of the local field enhancement in a hyperbolic medium associated with ENZ and ENP dispersion points in the appearance of magneto-optical activity of magnetic hyperbolic metamaterials.

[THE IDENTIFICATION OF ALTERATIONS IN THE AREA OF GREAT DUODENAL PAPILLA AND MICRO-CHOLELITHIASIS AS A TECHNIQUE OF PREVENTION OF POST-CHOLECYSTECTOMY SYNDROME AFTER MINI-INVASIVE CHOLECYSTECTOMY].

The article presents the results of endoscopic and laboratory analyses of bile in 90 patients after mini-invasive cholecystectomy The significant amount of endoscopic diagnosed alterations in the area of major duodenal papilla that amounted to 64.4% of examined patients and also occurrence of micro-cholelithiasis and insoluble precipitates in analyzed bile of 83.3% of patients. The derived data testifies necessity of application of pre-operational endoscopic diagnostic of alterations in the area of major duodenal papilla and in post-operative period as well completing it by analysis of native bile preparation.

Interactions and compatibility of 11 S globulin from Vicia faba seeds and sodium salt of carboxymethylcellulose in an aqueous medium.

This work studies specific interactions and compatibility between a legumin and a linear carboxylated polysaccharide using gel permeation chromatography, sedimentation analysis, SDS gel electrophoresis, viscometry and phase analysis measurements. It uses the system water/11 S globulin/CMC as a model. Carboxymethylcellulose (CMC) molecules are able to cause a partial dissociation of the protein, subsequent formation of soluble interbiopolymeric complexes and partial aggregation of the free non combined protein at room temperature and pH 6.0-6.5. The maximal binding of biopolymers is observed at their equimolar ratio. The decrease in temperature of the mixture from 293 to 277 K leads to formation of the complex coacervate. The increase in pH from 6.0 to 7.6 results in suppression of complex formation and manifestation of the phenomenon of thermodynamic incompatibility if the total concentration of biopolymers in the system exceeds the critical concentration of segregative phase separation.

Interfacing the radiology information system to the modality: an integrated approach.

The radiology information system (RIS) provides patient and examination information that is used in setting up and performing a radiologic procedure. In a digital imaging environment, information from the RIS can also be used to populate fields in the Digital Imaging and Communications in Medicine (DICOM) image header. Ideally, information from the RIS should be available at the modality at the time of the examination, and automatically be attached to the image in the appropriate DICOM fields before storage in the picture archiving and communications system (PACS). We have designed a highly integrated RIS interface for a digital radiography (DR) system. This interface employs browser technology to make RIS information conveniently available at the modality, and DICOM modality performed procedure step (MPPS) for RIS/DR information exchange. A novel feature of our approach is that a single display screen at the modality is used to alternatively display either the modality control window or the RIS window. Full access to RIS capabilities is available at the modality, including worklists and prior reports.

Serum lipoproteins of patients with glycogen storage disease.

Seventeen patients with different types of glycogen storage disease (GSD) were under observation. The type of the disease was defined from glucaemic and lactotaemic curves obtained in glucose, galactose and adrenaline tolerance tests and by biochemical analysis of liver biopsy specimens. Seven patients were found to have Type I; five patients, Type III; one patient, Type VI; and four patients, the Type IX (or X) of GSD. The serum lipoprotein (LP) content was determined in all patients using analytical ultracentrifugation. Hyperlipoproteinaemia (HLP) was found in virtually all patients. Patients with Type I of GSD were found to have Types 2b and 4 of HLP; and patients with Type III of GSD, 2b Type of HLP. 2a Type of HLP was diagnosed in patients with GSD of VI and IX (X) Types. Patients with Type III GSD, in contrast to those with GSD of other types, had enhanced levels of Sf 12-20 LP. The levels of Sf 100-400 and Sf 20-100 LP were greatly increased only in patients with Type I GSD.