Highly Regular Laser-Induced Periodic Surface Structures on Titanium Thin Films for Photonics and Fiber Optics.

Modern photonic devices demand low-cost, scalable methods for creating periodic patterns over diverse surfaces including nonplanar and tipped ones, the examples of which can be readily found in fiber optics. Laser-induced periodic surface structures (LIPSS) offer an attractive route for fabricating such patterns in a single-step straightforward procedure, where the temporal and spatial locality of the self-interference effects ensure robustness against variations of the laser processing parameters. In this work, we show the LIPSS-assisted oxidation of thin titanium films by near-IR femtosecond laser pulses as a promising technology for the production of regular gratings consisting of rutile ridges.

Pressure dependence of intermediate-range order and elastic properties of glassy Baltic amber.

Amber is a unique example of a fragile glass that has been extensively aged below its glass transition temperature, thus reaching a state that is not accessible under normal experimental conditions. We studied the medium-range order of Baltic amber by x-ray diffraction (XRD) at high pressures. The pressure dependences of the low-angle XRD intensity between 0 and 5 Å^{-1} were measured from 0 to 7.

IR Hidden Patterns for Security Labels.

Authentication of a product's originality by anticounterfeiting labels represents a crucial point toward protection against forgery. Fast and scalable fabrication methods of original labels with a high degree of protection are in high demand for the protection of valuable goods. Here, we propose a simple strategy for fabrication of hidden security tags with IR luminescent readout by the direct femtosecond laser patterning of silicon-erbium-silicon sandwiched thin films.

Probing metabolism in mouse embryos using Raman spectroscopy and deuterium tags.

The use of deuterated compounds is an interesting opportunity to expand the capabilities of Raman spectroscopy to study metabolism in living cells. Different biological objects have different tolerances to different deuterated compounds, and their metabolic chains may differ. Here, we explore the potential of this approach to probe metabolism in early mouse embryos.

Newest Methods and Approaches to Enhance the Performance of Optical Frequency-Domain Reflectometers.

In this review, we summarize the latest advances in the design of optical frequency-domain reflectometers (OFDRs), digital signal processing, and sensors based on special optical fibers. We discuss state-of-the-art approaches to improving metrological characteristics, such as spatial resolution, SNR, dynamic range, and the accuracy of determining back reflection coefficients. We also analyze the latest achievements in the OFDR-based sensors: the accuracy of spatial localization of the impact, the error in detecting temperatures, deformation, and other quantities, and the features of separate measurement of various physical quantities.

Raman Lasing and Transverse Mode Selection in a Multimode Graded-Index Fiber with a Thin-Film Mirror on Its End Face.

Multimode fibers are attractive for high-power lasers if transverse modes are efficiently controlled. Here, a dielectric thin-film mirror (R~20%) is micro-fabricated on the central area of the end face of a 1 km multimode 100/140 µm graded-index fiber and tested as the output mirror of a Raman laser with highly multimode (M~34) 940 nm diode pumping. In the cavity with highly reflective input FBG, Raman lasing of the Stokes wave at 976 nm starts at the threshold pump power of ~80 W.

Temperature dependence of spatial nanoheterogeneities of shear modulus in supercooled glycerol.

The boson peak in the terahertz vibrational spectrum carries information about nano-heterogeneities in the shear modulus in glass formers. Its evolution upon heating or cooling in a supercooled liquid state may shed light on the temperature dependence of heterogeneities. For this purpose, an analysis of the light scattering spectra of supercooled glycerol in the spectral range of the boson peak and fast relaxation was carried out and the parameters of the boson peak in the temperature range 180-330 K were determined.

Reversed Corneal Fibroblasts Therapy Restores Transparency of Mouse Cornea after Injury.

Cell-based therapies using corneal stromal stem cells (CSSC), corneal keratocytes, or a combination of both suppress corneal scarring. The number of quiescent keratocytes in the cornea is small; it is difficult to expand them in vitro in quantities suitable for transplantation. This study examined the therapeutic effect of corneal fibroblasts reversed into keratocytes (rCF) in a mouse model of mechanical corneal injury.

Brillouin spectroscopy of medically relevant samples of bovine jugular vein and pericardium.

There is the rapid growth in application of Brillouin scattering spectroscopy to biomedical objects in order to characterize their mechanoelastic properties in this way. However, the possibilities and limitations of the method when applied to tissues have not yet been clarified. Here, applicability of Brillouin spectroscopy for testing the elastic response of medically relevant tissues of bovine jugular vein and pericardium was considered.

Reversal of crystallization in cryoprotected samples by laser editing.

Advances in cryobiology techniques commonly target either the cooling or the warming cycle, while little thought has been given to ≪repair≫ protocols applicable during cold storage. In particular, crystallization is the dominant threat to cryopreserved samples but proceeds from small nuclei that are innocuous if further growth is forestalled. To this end, we propose a laser editing technique that locally heats individual crystals above their melting point by a focused nanosecond pulse, followed by amorphization during rapid resolidification.

Raman scattering spectroscopy of MBE grown thin film topological insulator BiSbTeSe.

BSTS epitaxial thin film topological insulators were grown using the MBE technique on two different types of substrates , Si (111) and SiC/graphene with BiSbTeSe and BiSbTeSe, respectively. The crystallographic properties of BSTS films were investigated X-ray diffraction, which showed the strongest reflections from the (0 0 ) facets corresponding to the rhombohedral phase. Superior epitaxial growth, homogeneous thickness, smooth surfaces, and larger unit cell parameters were observed for the films grown on the Si substrate.

Effects of stearic acid on the embryo cryopreservation in mouse.

Background: Intracellular lipids are sensitive to freezing. Lipidome modification is an important tool for studying the role of intracellular lipids in cryotolerance of mammalian oocytes and preimplantation embryos.

Objective: To study the effects of in vitro exposure of murine embryos to saturated stearic acid (SA) on the lipid content, embryo development and cryotolerance.

Irreversible lipid phase transition detected in a porcine oocyte at chilling.

Under physiological conditions, the membranes and lipid droplets of germ cells are in a conformationally disordered phase. Typically, during cooling, lipids undergo the transition to ordered phases and, upon heating, melt into a disordered phase. In this communication, we report the lipid phase transition in lipid droplets observed in porcine oocytes.

Program freezing of diapausing embryos in the mouse.

Embryonal diapause is a characteristic feature of about 130 mammalian species. However, very few studies have addressed cryopreservation of diapausing embryos. This work is aimed to apply program freezing to blastocysts obtained from CD1 mice, which were at diapause state after ovariectomy and the subsequent hormonal therapy.

Nonlinear Optical Pulses in Media with Asymmetric Gain.

A generic novel model governing optical pulse propagation in a nonlinear dispersive amplifying medium with asymmetric (linear spectral slope) gain is introduced. We examine the properties of asymmetric optical pulses formed in such gain-skewed media, both theoretically and numerically. We derive a dissipative optical modification of the classical shallow water equations that highlights an analogy between this phenomenon and hydrodynamic wave breaking.

Standard operating procedure to reveal prostate cancer specific volatile organic molecules by infrared spectroscopy.

The growing number of prostate cancer cases is a real concern in modern society. Over 1.4 million new cases and about 400 thousand (>26%) deaths were registered worldwide in 2020 due to prostate cancer.

Self-pressurised rapid freezing at arbitrary cryoprotectant concentrations.

Self-pressurised rapid freezing (SPRF) has been proposed as a simple alternative to traditional high-pressure freezing (HPF) protocols for vitrification of biological samples in electron microscopy and cryopreservation applications. Both methods exploit the circumstance that the melting point of ice reaches a minimum when subjected to pressure of around 210 MPa, however, in SPRF its precise quantity depends on sample properties and hence, is generally unknown. In particular, cryoprotective agents (CPAs) are expected to be a factor; though eschewed by many SPRF experiments, vitrification of larger samples notably cannot be envisaged without them.

Raman spectroscopy of yeast cells cultured on a deuterated substrate.

Raman spectroscopy of cells cultured in a deuterated substrate is a promising approach to the characterization of mass transfer and enzymatic reactions in living cells. Here, we studied the potential of this approach using the example of yeast cells cultured under aerobic and anaerobic conditions. In our experiments, unadapted to DO Saccharomyces cerevisiae were cultured in a medium with different concentrations of deuterium oxide and deuterated glucose.

In-plane and out-of-plane gigahertz sound velocities of saturated and unsaturated phospholipid bilayers from cryogenic to room temperatures.

Here, we examined the gigahertz sound velocities of hydrated multibilayers of saturated (1,2-dimyristoyl-sn-glycero-3-phosphocholine, DMPC) and unsaturated (1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC) phospholipids by Brillouin spectroscopy. Out-of-plane and in-plane (lateral) phonons were studied independently of each other. Similar strong temperature dependences of the sound velocities were found for phonons of both types.

Characterization of conformational states of POPC and DPPC in POPC/DPPC/cholesterol mixtures using Raman spectroscopy.

Conformational states of phospholipid chains in ternary mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), deuterated 1,2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (DPPC), and cholesterol (Chol) were studied by Raman spectroscopy. Parameters of Raman peaks sensitive to conformational order have been used to determine chain order for mixtures over a wide range of compositions. A ternary diagram of fractions of phospholipid chains in conformationally ordered and disordered states has been constructed.

Towards Topology-Free Programming for Cyber-Physical Systems with Process-Oriented Paradigm.

The paper proposes a topology-free specification of distributed control systems by means of a process-oriented programming paradigm. The proposed approach was characterized, on the one hand, by a topologically independent specification of the control algorithm and, on the other hand, by the possibility of using existing formal verification methods by preserving the semantics of a centralized process-oriented program. The paper discusses the advantages of a topologically independent specification of distributed control systems, outlines the features of control software, argues why the use of a process-oriented approach to the development of the automation of cyber-physical systems is suitable for solving these problems, describes a general scheme for implementing a distributed control system according to a process-oriented specification, and proposes a formal heuristic algorithm for partitioning a sequential process-oriented program into independent clusters.

Influence of Single-Wall Carbon Nanotube Suspension on the Mechanical Properties of Polymeric Films and Electrospun Scaffolds.

Carbon nanotubes (CNTs) are used in applications ranging from electrical engineering to medical device manufacturing. It is well known that the addition of nanotubes can influence the mechanical properties of various industrial materials, including plastics. Electrospinning is a popular method for fabricating nanomaterials, widely suggested for polymer scaffold manufacturing.

Metastable states in the J_{1}-J_{2} Ising model.

We study the J_{1}-J_{2} Ising model on the square lattice using the random local field approximation (RLFA) and Monte Carlo (MC) simulations for various values of the ratio p=J_{2}/|J_{1}| with antiferromagnetic coupling J_{2}, ensuring spin frustration. RLFA predicts metastable states with zero order parameter (polarization) at low temperature for p∈(0,1). This is supported by our MC simulations, in which the system relaxes into metastable states with not only zero, but also with arbitrary polarization, depending on its initial value, external field, and temperature.

Characterization of susceptibility artifacts in magnetic resonance thermometry images during laser interstitial thermal therapy: dimension analysis and temperature error estimation.

Laser interstitial thermal therapy (LITT) is a minimally invasive procedure used to treat a lesion through light irradiation and consequent temperature increase. Magnetic resonance thermometry imaging (MRTI) provides a multidimensional measurement of the temperature inside the target, thus enabling accurate monitoring of the damaged zone during the procedure. In proton resonance frequency shift-based thermometry, artifacts in the images may strongly interfere with the estimated temperature maps.