Characteristics of stroke service implementation in Armenia.

Background: Acute stroke care service in Armenia was established in 2019 after the implementation of the National Stroke Program (NSP). This study aimed to provide an up-to-date account of the current image and clinical characteristics of acute stroke service implementation at a tertiary hospital in Armenia by analyzing the quality of care and identifying the areas that need improvement.

Methods: We analyzed patient data from a single hospital in 1 year after the establishment of acute stroke care service (February 2021-January 2022).

Effect of visible light onto self-assembly in l-cysteine-silver solution.

Effects of irradiation with visible light on the process of self-assembly in an aqueous l-cysteine-silver solution (CSS) and hydrogels based on were investigated using a set of physico-chemical methods. It was found that the exposure to light of CSS and hydrogels based on l-cysteine and silver acetate colors them firstly into yellow and subsequently to brown, which is due to the plasmon resonance of free electrons at the surface of resulting silver nanoparticles (AgNPs). A mechanism involving participation of AgNPs was proposed for the self-assembly in CSS and hydrogel.

Suppression of low-frequency charge noise in superconducting resonators by surface spin desorption.

Noise and decoherence due to spurious two-level systems located at material interfaces are long-standing issues for solid-state quantum devices. Efforts to mitigate the effects of two-level systems have been hampered by a lack of knowledge about their chemical and physical nature. Here, by combining dielectric loss, frequency noise and on-chip electron spin resonance measurements in superconducting resonators, we demonstrate that desorption of surface spins is accompanied by an almost tenfold reduction in the charge-induced frequency noise in the resonators.

Direct Identification of Dilute Surface Spins on Al_{2}O_{3}: Origin of Flux Noise in Quantum Circuits.

An on-chip electron spin resonance technique is applied to reveal the nature and origin of surface spins on Al_{2}O_{3}. We measure a spin density of 2.2×10^{17}  spins/m^{2}, attributed to physisorbed atomic hydrogen and S=1/2 electron spin states on the surface.

Charge qubit coupled to an intense microwave electromagnetic field in a superconducting Nb device: evidence for photon-assisted quasiparticle tunneling.

We study a superconducting charge qubit coupled to an intensive electromagnetic field and probe changes in the resonance frequency of the formed dressed states. At large driving strengths, exceeding the qubit energy-level splitting, this reveals the well known Landau-Zener-Stückelberg interference structure of a longitudinally driven two-level system. For even stronger drives, we observe a significant change in the Landau-Zener-Stückelberg pattern and contrast.

A near-field scanning microwave microscope based on a superconducting resonator for low power measurements.

We report on the design and performance of a cryogenic (300 mK) near-field scanning microwave microscope. It uses a microwave resonator as the near-field sensor, operating at a frequency of 6 GHz and microwave probing amplitudes down to 100 μV, approaching low enough photon population (N ∼ 1000) of the resonator such that coherent quantum manipulation becomes feasible. The resonator is made out of a miniaturized distributed fractal superconducting circuit that is integrated with the probing tip, micromachined to be compact enough such that it can be mounted directly on a quartz tuning-fork, and used for parallel operation as an atomic force microscope (AFM).

Immunohistochemical characteristics of desmoid tumors.

A comparative morphological study of primary and relapsing desmoid tumors was carried out. Immunohistochemical analysis showed that the progress of desmoid tumors in the form of relapses was paralleled by an increase in the counts of immunopositive cells and intensity of β-catenin and cycloxygenase-2 expression.

Poly(2-hydroxyethyl methacrylate) emboli with increased haemostatic effect for correction of haemorrhage of complex origin in endovascular surgery of children.

Poly(2-hydroxyethyl methacrylate) (PHEMA) embolization particles with enhanced haemostatic properties were prepared by bulk or suspension polymerisation of 2-hydroxyethyl methacrylate (HEMA) followed by particle soaking in ethamsylate solution. The particles accelerated thrombus formation as evidenced by blood analysis of rabbits with implanted emboli. Usefulness of both spherical and cylindrical PHEMA particles with enhanced haemostatic effect was demonstrated on the embolization of arterial anastomosis, fistulas of the lower extremity and abdominal cavity, haemangioma and arteriovenous malformation of the head of several children.

Poly(2-hydroxyethyl methacrylate) microspheres/liquid poly(dimethylsiloxane) composition for correction of small defects in face: histological evaluation in animal experiment.

Two kinds of composition based on commercial liquid poly(dimethylsiloxane) and laboratory-made poly(2-hydroxyethyl methacrylate) (PHEMA) microspheres of different size fractions (30-40 or 125-180 microm) were prepared. Tissue reaction on injection of the compositions, optimum microsphere size and morphology were investigated in the experiments on rats. The microspheres induced foreign body reaction characterized by an increased content of fibroblasts and mild infiltration of injection field by inflammatory cells.

Proliferative activity of adipocytes in adipose tissue tumors.

Electron-autoradiographic study of normal and tumor-transformed adipose tissue (common lipoma and destructive lipoma, i.e. infiltrating and degrading lipoma) showed the capacity of adipose tissue cells in lipomas, especially in destructive lipomas, to proliferation and differentiation.

Poly(HEMA)--based embolic material in endovascular surgery of liver.

Physico-chemical and medico-biological methods, including hematology and cytology, were used in an evaluation of properties of poly(2-hydroxyethyl methacrylate) (poly(HEMA))-based embolic material indicated in the occlusion of branches of hepatic artery of patients with focal alterations of the liver. The elastographic method helped in predicting mechanical properties of the hydrogel material. Poly(HEMA) was mechanically stable for endovascular applications, exhibited no significant loss in elasticity and possessed consistency resembling the soft tissue of the organism.

Specific effect of epidermal growth factor immobilized on wound coating with soluble collagen on healing of experimental wounds.

Electron-microscopy and autoradiography of granulation tissue in wounds showed that bioactive coating with epidermal growth factor activates functional and proliferative processes in vascular cells (endotheliocytes and pericytes) and fibroblasts and increases the number of cell-to-cell contacts on days 2-3 of therapy. Pronounced activation of proliferative processes resulted in early differentiation of fibroblast cells (on days 3-4) and rapid epithelialization of the wound.

Targeted chemoembolization of tumors with poly(2-hydroxyethyl methacrylate) particles.

Thirty-four patients suffering from various kinds of tumors, including metastasis, were treated by selective embolization with both spherical and cylindrical poly(2-hydroxyethyl methacrylate) [poly(HEMA)] particles and topical chemotherapy. Treatment of a patient with carcinoid metastases in the liver is discussed. Immediately after embolization, 5-fluorouracil, and later, doxorubicin and Lipiodol, were selectively infused into the tumorous tissue for approximately 1 week.

Crab collagenase in wound debridement.

A comparative study was performed of the caseinolytic, necrolytic and fibrinolytic activities of a crab collagenase product prepared from the hepatopancreas of the king crab (Paralithodes camtschatica) and four enzyme preparations (trypsin/chymotrypsin and protease complexes isolated from Aspergillus terricola, Carica papaya and pseudomonodaceae). This paper reports an in vitro investigation, an in vivo study with rats and a clinical evaluation. It was found that crab collagenase has the highest proteolytic activity measured with respect to fibrin clot and necrotic eschar in vitro although its caseinolytic activity is the lowest.

Crab collagenase in wound debridement.

A comparative study was performed of the caseinolytic, necrolytic and fibrinolytic activities of a crab collagenase product prepared from the hepatopancreas of the king crab (Paralithodes camtschatica) and four enzyme preparations (trypsin/chymotrypsin and protease complexes isolated from Aspergillus terricola, Carica papaya and pseudomonodaceae). This paper reports an in vitro investigation, an in vivo study with rats and a clinical evaluation. It was found that crab collagenase has the highest proteolytic activity measured with respect to fibrin clot and necrotic eschar in vitro although its caseinolytic activity is the lowest.

Poly (2-hydroxyethyl methacrylate) particles for management of hemorrhage of complicated origin: treatment of hemobilia.

Poly (2-hydroxyethyl methacrylate) (PHEMA) particles of cylindrical and spherical shape were developed as a preparation for tumor treatment or control of hemorrhage by blocking their blood supply. In this report, PHEMA particles were used for the management of hemobilia, that is, bleeding into biliary passages. The origin of hemobilia in 31 patients was localized by selective angiography.

Poly(2-hydroxyethyl methacrylate) particles for preoperative endovascular occlusion of extensive angiodysplasias.

The application of superselective endovascular occlusion in vascular radiology has broadened the scope of possible radical surgery of giant angiodysplasias by reducing considerably the risk of severe haemorrhage during the surgery. Occlusion was performed on 229 patients using spherical and cylindrical particles of porous poly(2-hydroxyethyl methacrylate). The treatment of a patient suffering from angiodysplasia of the pelvis is described as an example.

Haemostatic activity of ethamsylate and aminocaproic acid adsorbed poly(2-hydroxyethyl methacrylate) particles.

A haemostatic material suitable for embolization was prepared by the adsorption of haemostatics--ethamsylate and aminocaproic acid in the spherical particles of porous poly(2-hydroxyethyl methacrylate) (p(HEMA)). The degree of purification of ethamsylate-treated particles was tested by an analysis of donor blood in contact with the material. An evaluation of the haemostatic properties of these materials was obtained by the determination of the indicators of blood clotting: activated partial thromboplastin time, thrombin time, and prothrombin time.