Experimental Method of Temperature and Strain Discrimination in Polymer Composite Material by Embedded Fiber-Optic Sensors Based on Femtosecond-Inscribed FBGs

Experimental method of temperature and strain discrimination with fiber Bragg gratings (FBGs) sensors embedded in carbon fiber-reinforced plastic is proposed. The method is based on two-fiber technique, when two FBGs inscribed in different fibers with different sensitivities to strain and/or temperature are placed close to each other and act as a single sensing element. The nonlinear polynomial approximation of Bragg wavelength shift as a function of temperature and strain is presented for this method. The FBGs were inscribed with femtosecond laser by point-by-point inscription technique through polymer cladding of the fiber. The comparison of linear and nonlinear approximation accuracies for array of embedded sensors is performed. It is shown that the use of nonlinear approximation gives 1.5–2 times better accuracy. The obtained accuracies of temperature and strain measurements are 2.6–3.8°C and 50–83 με in temperature and strain range of 30–120°C and 0–400 με, respectively

Helicity components of the cross section for double charged-pion production by real photons on protons

The helicity components σ1/2 and σ3/2 of the cross section for double charged-pion production by real photons on a nucleon are calculated within a phenomenological approach developed previously. A high sensitivity of the σ1/2–σ3/2 asymmetry to the contribution of nucleon resonances having strongly different electromagnetic helicity amplitudes A1/2 and A3/2 is demonstrated. This feature is of importance for seeking "missing" baryon states

4-(Aryl)-Benzo[4,5]imidazo[1,2-a]pyrimidine-3-Carbonitrile-Based Fluorophores: Povarov Reaction-Based Synthesis, Photophysical Studies, and DFT Calculations

A series of novel 4-(aryl)-benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles were obtained through the Povarov (aza-Diels–Alder) and oxidation reactions, starting from benzimidazole-2-arylimines. Based on the literature data and X-ray diffraction analysis, it was discovered that during the Povarov reaction, [1,3] sigmatropic rearrangement leading to dihydrobenzimidazo[1,2-a]pyrimidines took place. The structures of all the obtained compounds were confirmed based on the data from 1H- and 13C-NMR spectroscopy, IR spectroscopy, and elemental analysis. For all the obtained compounds, their photophysical properties were studied. In all the cases, a positive emission solvatochromism with Stokes shifts from 120 to 180 nm was recorded. Aggregation-Induced Emission (AIE) has been illustrated for compound 6c using different water fractions (fw) in THF. The compounds 6c and 6f demonstrated changes in emission maxima or/and intensities after mechanical stimulation

2-Furyl-6-nitro-1,2,4-triazolo [1,5-a]pyrimidin-7-one

A sodium salt of 2-(fur-2-yl)-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one as a close structural analogue of ZM-241385 was obtained. This heterocycle can serve as an effector for A2a adenosine receptors and possesses antiseptic activity. The structures of compounds were confirmed based on the data of 1H, 13C NMR spectroscopy, IR spectroscopy, and an elemental analysis. The structure of sodium salt 2-furyl-6-nitro-1,2,4-triazolo[1,5-a]pyrimidin-7-one was confirmed by an X-ray diffraction analysis

Azolo[1,5-<i>a</i>]pyrimidines and Their Condensed Analogs with Anticoagulant Activity

Hypercytokinemia, or cytokine storm, is one of the severe complications of viral and bacterial infections, involving the release of abnormal amounts of cytokines, resulting in a massive inflammatory response. Cytokine storm is associated with COVID-19 and sepsis high mortality rate by developing epithelial dysfunction and coagulopathy, leading to thromboembolism and multiple organ dysfunction syndrome. Anticoagulant therapy is an important tactic to prevent thrombosis in sepsis and COVID-19, but recent data show the incompatibility of modern direct oral anticoagulants and antiviral agents. It seems relevant to develop dual-action drugs with antiviral and anticoagulant properties. At the same time, it was shown that azolo[1,5-a]pyrimidines are heterocycles with a broad spectrum of antiviral activity. We have synthesized a new family of azolo[1,5-a]pyrimidines and their condensed polycyclic analogs by cyclocondensation reactions and direct CH-functionalization and studied their anticoagulant properties. Five compounds among 1,2,4-triazolo[1,5-a]pyrimidin-7-ones and 5-alkyl-1,3,4-thiadiazolo[3,2-a]purin-8-ones demonstrated higher anticoagulant activity than the reference drug, dabigatran etexilate. Antithrombin activity of most active compounds was confirmed using lipopolysaccharide (LPS)-treated blood to mimic the conditions of cytokine release syndrome. The studied compounds affected only the thrombin time value, reliably increasing it 6.5–15.2 times as compared to LPS-treated blood

4-(Aryl)-Benzo[4,5]imidazo[1,2-<i>a</i>]pyrimidine-3-Carbonitrile-Based Fluorophores: Povarov Reaction-Based Synthesis, Photophysical Studies, and DFT Calculations

A series of novel 4-(aryl)-benzo[4,5]imidazo[1,2-a]pyrimidine-3-carbonitriles were obtained through the Povarov (aza-Diels–Alder) and oxidation reactions, starting from benzimidazole-2-arylimines. Based on the literature data and X-ray diffraction analysis, it was discovered that during the Povarov reaction, [1,3] sigmatropic rearrangement leading to dihydrobenzimidazo[1,2-a]pyrimidines took place. The structures of all the obtained compounds were confirmed based on the data from 1H- and 13C-NMR spectroscopy, IR spectroscopy, and elemental analysis. For all the obtained compounds, their photophysical properties were studied. In all the cases, a positive emission solvatochromism with Stokes shifts from 120 to 180 nm was recorded. Aggregation-Induced Emission (AIE) has been illustrated for compound 6c using different water fractions (fw) in THF. The compounds 6c and 6f demonstrated changes in emission maxima or/and intensities after mechanical stimulation

Laser in Pediatric Dentistry

Laser technology has different applications in dentistry, and, particularly, in Paediatric Dentistry. Depending on laser wavelengths and the physical properties of the tissue which is to be targeted; it is possible obtain different results in three main dental fields: Diagnosis, Prevention and Operative Therapy. Conventional treatments can sometimes be replaced by laser treatments and better results may be achieved. Laser treatments offer new treatment opportunities in the dental field that were unknown in the past. This chapter aims to outline the clinical protocols and possible applications of different laser systems in Paediatric Dentistry