Observation of Linear and Nonlinear Light Localization at the Edges of Moiré Arrays

We observe linear and nonlinear light localization at the edges and in the corners of truncated moiré arrays created by the superposition of periodic mutually twisted at Pythagorean angles square sublattices. Experimentally exciting corner linear modes in the femtosecond-laser written moiré arrays we find drastic differences in their localization properties in comparison with the bulk excitations. We also address the impact of nonlinearity on the corner and bulk modes and experimentally observe the crossover from linear quasilocalized states to the surface solitons emerging at the higher input powers. Our results constitute the first experimental demonstration of localization phenomena induced by truncation of periodic moiré structures in photonic systems.

[Enhanced Natural Killers with CISH and B2M Gene Knockouts Reveal Increased Cytotoxicity in Glioblastoma Primary Cultures]

In an experimental study using the CRISPR/Cas9 system, "enhanced" NK cell lines with knockout of CISH, the gene for the CIS protein (a negative regulator of NK cytotoxicity), as well as two lines with a knocked-out β2-microglobulin gene, which provides membrane exposure of MHC class I, were obtained from two parental lines of human natural killers (YT wild type and YT-VAV1^(+) overexpressing the VAV1 cytotoxicity enhancing protein). The knockout efficiency was determined by real-time PCR as well as by flow cytometry with specific antibodies. The resulting CISH^(-/-) or B2M^(-/-) knockout lines were tested for cytotoxicity in primary monolayer cultures of human glioblastoma multiforme. The cytotoxicity of the lines was assessed using a cell analyzer that records the cell index based on cell impedance. YT-CISH^(-/-) has been shown to be significantly more effective than wild-type YT in eliminating primary glioblastoma cells in an in vitro cell monolayer experiment. The cytotoxicity of the YT-VAV1^(+)-CISH^(-/-) and YT-VAV1^(+)B2M^(-/-) lines against glioblastoma cells was the highest, but overall, it did not significantly differ from the initially increased cytotoxicity of the YT-VAV1^(+) line. The lines of NK-like cells obtained may serve as a prototype for the creation of "enhanced" allogeneic and autologous NK- and CAR-NK cells for the immunotherapy of glioblastoma multiforme.

Observation of Edge Solitons in Topological Trimer Arrays

We report the experimental observation of nonlinear light localization and edge soliton formation at the edges of fs-laser written trimer waveguide arrays, where transition from nontopological to topological phases is controlled by the spacing between neighboring trimers. We found that, in the former regime, edge solitons occur only above a considerable power threshold, whereas in the latter one they bifurcate from linear states. Edge solitons are observed in a broad power range where their propagation constant falls into one of the topological gaps of the system, while partial delocalization is observed when considerable nonlinearity drives the propagation constant into an allowed band, causing coupling with bulk modes. Our results provide direct experimental evidence of the coexistence and selective excitation in the same or in different topological gaps of two types of topological edge solitons with different internal structures, which can rarely be observed even in nontopological systems. This also constitutes the first experimental evidence of formation of topological solitons in a nonlinear system with more than one topological gap.

[Prognostic significance of leukocyte count in the venous blood in the acute stage of cerebral aneurism rupture]

AIM

To determine a prognostic role of leukocyte count in the venous blood in the acute stage of cerebral aneurysm (CA) rupture.

MATERIAL AND METHODS

Fifty-one patients with CA rupture, aged from 20 to 65 years, hospitalized in the first 72 h over the period from 01.10.12 to 01.02.16 were examined. The severity of disease and anatomical form of hemorrhage was corresponded to III-IV degree on the W. Hunt - R. Hess scale and Fisher scale. All patients underwent surgery. Outcomes after open and endovascular surgeries were similar.

RESULTS

Normal leukocyte number in the venous blood at admission was identified in 12 (24%) of patients (on average 7.3±1.4·109/L), leukocytosis in 39 (76%) (14.3±3.1·109/L) (p<0.0001). Leukocyte number in the acute stage of CA rupture was correlated with the frequency and severity of the vessel spasm. In 28 (55%) of patients with ischemic lesions of the brain matter, mean leukocyte number in the first 72 h after hemorrhage was higher by 2-24% (3±4.8·109/L) compared to patients without ischemia (11.9±2.5·109/L) (p=0.06). The level of leukocytes in survivors was lower by 3 - 28% (122±3.4·109/L) compared to patients with fatal outcome and patients with severe neurological deficit after the surgery (14.5±3.9·109/L) (p>0.05).

CONCLUSION

The increase in leukocyte number in the venous blood in the first 72 h after CA rupture ≥10,1·109/L is a reliable risk factor of marked vessel spasm. The level of leukocytes in patients with cerebral ischemia and poor prognosis in the first 72h after aneurysmal hemorrhage was higher by 2-28% compared to survivors without neurological impairment or mild neurological deficit.

Laser-written polarizing directional coupler with reduced interaction length

Integrated optical waveguides, manufactured with femtosecond laser writing (FSLW) technology, enable precise control and manipulation of light in complicated photonic chips. However, due to the intrinsically low anisotropy of FSLW waveguides, polarizing integrated devices have had a relatively large footprint. In this Letter, we demonstrate an approach based on stress-induced anisotropy, allowing us to decrease the size of polarizing directional couplers down to 3.7 mm, almost an order of magnitude shorter than previously reported. The measured extinction ratios at the wavelength of 808 nm are 16 dB and 20 dB for the horizontal and vertical polarizations, respectively. We provide a possible theoretical model for the observed effects.