5th International Conference on Nanotechnologies and Biomedical Engineering

We report in this paper the results of theoretical investigations of the influence of double feedback on the stationary states of quantum dots lasers. The Bloch equations model was used to simulate and analyze these states. We have identified the distribution of external cavity modes varying the feedback strength.

The photon quantum dynamics in a damped single-mode quantized cavity field coupled with a resonantly driven two-level system possessing nonzero permanent dipoles is investigated here. The interacting subsystems are very different frequencies (microwave and optical domains) and, in this highly dispersive regime, the emitter couples to the resonator mode via its diagonal dipole moments only. As a result, this interaction regime is responsible for the cavity multiphoton quantum dynamics and photon conversion from optical to terahertz ranges, for instance. Furthermore, enhanced terahertz photon correlations occur as well.

In this work, the individual hexagonal boron nitride (h-BN) microtubular structures with different diameter (ranging from ≈0.2 to ≈2.5 μm) and a wall thickness below 25 nm were investigated for the first time by integration on SiO2/Si substrate using a method based on focused ion beam deposition (FIB/SEM). The current-voltage (I-V) measurements were carried out in from a bias of −40 V to +40 V and in a temperature range from 25 to 100 ℃. All fabricated devices showed excellent insulating properties and the resistance of ≈111 GΩ was calculated, which was attributed mainly to the top SiO2 layer of the substrate measured without h-BN. The obtained results elucidate the excellent potential of the boron nitride microtubular structures with nanowalls to be used as high-quality shielding materials of other nano- and microstructures for application in nanoelectronics, nanophotonics and power electronics, where a relatively wide range of operating temperature is necessary.

Modern subterahertz-terahertz (subTHz-THz) technologies, including 5G and 6G wireless telecommunication and THz optoelectronics, apply for working frequency range of tens of gigahertz to several terahertz (millimeter-submillimeter wavelengths). Demanded flexibility of various application calls for thorough investigation of materials with tunable functional characteristics. Understanding the physical mechanisms responsible for tunability of the specific parameters of materials paves the way for targeted controlling their properties and, in turn, allows to choose the material with desired parameters for the particular (and/or even multiple) applications when designing specific devices. Here, we discuss the influence of the variation of the form of material (nanoceramics, powders, single crystals) as well as of the grain sizes, and preparation conditions, on the dielectric and magnetic characteristics of the ferromagnetic hexaferrites and epsilon iron oxide that are among most perspective materials to be used for fabrication of elements and devices of future optoelectronics. The prospects of their potential applications are discussed in detail.

In this paper Zn1-xMgxO thin films with composition range x = 0.00–0.80 have been obtained by aerosol spray deposition method on p-Si substrates by using zinc acetate and magnesium acetate as precursors. The produced thin films were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), and optical spectroscopy. SEM images revealed uniform nanocrystalline morphology of films, but the form of nanocrystals vary with variation of the Mg content. XRD analysis suggests that the produced films contain a wurtzite Zn1-xMgxO phase in the whole chemical composition range, with cubic phase MgO nanocrystalline inclusions with mean grain size around 20 nm. The optical bandgap was found to vary from 3.4 eV to 5.2 eV with increasing the Mg content from 0 to 60%.

In this study, the laser processing of thermally annealed TiO2 thin films at 420 ℃ in hydrogen atmosphere, utilizing an pulsed fourth-harmonic generation Nd: YAG laser employing different laser intensities in the atmosphere at room temperature, has been reported. Further, the surface morphology and crystalline structure have been investigated by means of atomic force microscopy [AFM], X-ray diffraction [XRD], Raman analysis. The AFM images obtained show that the film’s surface changes as the effect of the laser processes. Moreover, XRD and Raman analysis of the TiO2 thin films indicate at the threshold laser intensity, Ith = 66 MW/cm2 of the fourth-harmonic generation Nd: YAG laser phase transition from atanase-rutile to a crystalline 100% rutile.

For the use of iron oxide nanoparticles (NPs) for medical purposes, they must have the following properties: low cytotoxicity, bioavailability, the possibility of large-scale production, etc. Nowadays, there are many approaches for the iron oxide NPs synthesis, including chemical, biological, physical methods, etc. In this research, a comparative analysis of the cytotoxicity of iron oxide (Fe3O4) NPs synthesized with chemical and biological methods was carried out. For chemical Fe3O4 NPs oleic acid was used as a stabilizer, while for biogenic NPs were used various extracts of O. basilicum. As research results showed, the synthesized chemical and biogenic NPs do not have any pronounced cytotoxicity in relation to the studied bacterial strains and human erythrocytes, which allows them to use for further in vivo studies.

In this work, we studied the relaxation parameters, he-p and hres, of three composite structures Cu/LiF, Cu/MgO, and Cu/Si, which have different types of a chemical bond between the substrates (ionic (LiF), ionic-covalent (MgO), and covalent (Si)) and differ in hardness (HCu = 0.6 GPa, HLiF, HMgO and HSi are 1.2, 7.5 and 8.2 GPa, respectively). For each type of substrates, coated systems (CSs) were fabricated with a following Cu film thickness: t1 = 85; t2 = 470 and t3 = 1000 nm. The behavior of relaxation parameters was examined over a wide range of loads, P = 2–900 mN, during nanoindentation. The elastic-plastic parameters were shown to depend on the CS type, as well as on the film thickness and the magnitude of the applied load.

In this paper we present a systematic study of bulk GaAs wafers and gold-decorated GaAs surfaces exhibiting hydrophilic and hydrophobic behaviors. The wetting properties can be switched to superhydrophilicity and superhydrophilicity by simple electrochemical etching providing engineered porous morphologies. The results open interesting technological perspectives for the exploitation of GaAs surfaces.

We discuss some general features of the elastic vibration spectrum in layered nanocomposites based on the newly developed approach. The focus is on the compounds without any layering symmetry and on the dependence of their properties on various parameters. Some regular general features of the spectrum are revealed by a numerical and analytical study. In particular, existence of invariant characteristics which allow classification of the whole band structure in a way similar to the Sturm-Liouville theory. The spectral lines become multidimensional surfaces in the space which includes a variation of material parameters. It is demonstrated that confinement, layering and material selection produce qualitatively new properties which can be useful in applications.

Nanostructured As-S-Sb-Te semiconductors were synthesized and characterized by X-ray fluorescence analyzer (XRF), X-ray diffraction, and optical absorption methods. The X-ray diffraction patterns of ivestigated powders show the presence of amorphous and nanocrystalline phases with the structural units As2S3, Sb2S3 and Sb2Te3. The transmission spectra in the region of wavenumbers ν = 1000 ÷ 6000 cm−1 show a high transparence just with a single weak absorption band at ν = 2340 cm−1 caused of the presence H2S impurity. For the alloys of (As2S3)x(Sb2S3)1-x system, with increasing of the Sb2S3 trigonal structural units in the above mentioned system, the absorption edge is shifted toward lower photon energy, that corresponds to the optical band band gap about Eg. = 2.34 eV for As2S3, 2.1 eV for (As2S3)0.65(Sb2S3)0.35, 1.92 eV for (As2S3)0.35(Sb2S3)0.65 and 1.73 eV for Sb2S3.

Europium(III) coordination compound Eu(TTA)3(Ph3PO)2 (1) {TTA = thenoyltrifluoroacetonate, Ph3PO = triphenylphosphine oxide} has been prepared and characterized. Powder samples of the complex have been characterized by thermogarvimetric analysis (TGA), optical transmission and photoluminescence (PL) spectroscopy. PL have been registered for different temperatures in the range 11–300 K. The PL spectra was detected as specific narrow emission bands of internal transitions 4f → 4f of the Eu3+ ion 5D0 → 7Fj (j = 0–4). The major bands are centered at ca 580, 595, 615, 650 and 698 nm. PL data can be interpreted in the framework of the mechanism of energy transfer from the organic ligand matrix to Eu3+ ion.

The surface-barrier photosensitive structures based on zinc diarsenide crystals with metals have been produced. The electrical and photovoltaic properties of these structures were investigated. The photocurrent spectra and electrical characteristics are determined by the parameters of the semiconductor and the physicochemical properties of the contacting metals.

The results of concrete hardening due to nanomodification using graphene of a mixture of sand and Portland cement, activated in a magnetofluidized layer, are presented. The magnetofluidized layer is a suspension of needle-shaped ferromagnetic elements in a rotating electromagnetic field. As a result of intensive movement and constrained impact between ferromagnetic elements and concrete particles, sand and cement are finely ground. The results of studies of structural changes in quartz sand and Portland cement during mechanical activation in a magnetically fluidized layer are presented and analyzed. Changes in the surface physical and mechanical properties of sand and cement in comparison with the initial samples were determined by X-ray diffractometry and IR spectroscopy. During the nanomodification of concrete, difficulties arise in the uniform distribution of graphene in the total volume due to the very small size of nanoparticles and its small amount. The magnetofluidized layer provides a high degree of mixing, which makes it possible to evenly distribute graphene in the volume of the concrete mixture components, while exerting an electromagnetic effect and crushing the raw components.

Sintering of ZnO + Me2O3 (Me = Al, Ga, In) powder via chemical vapor transport based on HCl has been developed. The electrical properties of ZnO thin films obtained by DC magnetron sputtering of ZnO ceramic targets have been studied. Transparency, morphology, crystallinity and crystallite size of thin films have also been investigated. ZnO:Ga thin films with a resistivity of 2.5 × 10–4 Ω⋅cm have been successfully obtained. The films doped with Al have lower conductivity due to weak sputtering of insoluble Al2O3 dielectric inclusions in ceramics. In the case of sintering of ZnO together with In2O3, a significant loss of the doping material is observed.

This paper is devoted to the investigations of the recording of 1-D and 2-D holographic gratings using thin films of polyepoxypropylcarbazole (PEPC) obtained by deposition from solutions and their use as registering media for. For the direct recording azopolymer films based on polyepoxypropylcarbazole: methyl red with magnetic particles of Fe2SO4 were used. Diffraction efficiency in transmission of the recorded gratings consisted ~34%. Morphology of films surface and obtained surface relief’s was investigated using AFM and good quality of films surfaces and obtained relief’s was shown. For the first time simultaneously surface and magnetic relief were directly recorded using PEPC thin films as registering media.

Tone modulation of lower esophageal sphincters (LES) via electrical stimulation is a novel method of gastroesophageal reflux disease (GERD) treatment. Traditionally for output are commonly used constant current drivers, based on different schematic solutions. This allows delivering same stimulation energy even in case of impedance change during patient movements or electrode contact aging or encapsulation. The aim of our work was to design and implement simple constant current driver with digital current control and ultra-low power consumption. This driver was used in a prototype of implantable LES stimulator (WPLES), which effectiveness was confirmed during animal tests.

The article is devoted to the improvement of technical solutions for laser diagnostics of formed elements of human blood using the method of spectrum interferometry, and the development of a method for analysis of the obtained speckle patterns. The developed laboratory stand was used to obtain images of speckles from human blood smears and described the main points of its further integration into the system of non-invasive blood analysis, as well as the development of the principle of image processing.

Pupillometry technique has gained an increased interest over the years as it allows to objectively assess patient’s consciousness and neuro-ophthalmological status by measuring pupillary light reflex (PLR). Chromatic pupillometry emerged with the discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs), blue light sensitive and contributors to PLR. Automated pupillometers have been developed over the years to quantitatively measure PLR but have a reduced possibility to be a widespread screening tool as they are expensive and not portable. In this study, a smartphone-based pupillometer was developed, taking advantage of this technology accessibility, low-cost price, and portability. Chromatic stimuli were considered in this smartphone-based pupillometer to assess the contribution of ipRGCs to PLR and allow the screening of the neuro-ophthalmological diseases. In this preliminary study, six healthy individuals participated and pupillometric data was collected using the smartphone application developed, testing different protocols and background light conditions. The system presented good quality of eye images acquired and good behaviour in pupil data extraction. The acquisition protocols tested showed promising results to be used for chromatic pupillometry, although increasing the number of participants is mandatory and further research is needed. Nevertheless, this study shows the potential of the developed pupillometer to function as low cost, portable and accessible screening tool for neuro-ophthalmological diseases.

In this paper we present a modified transmission digital holographic microscope that can be used to image the state of polarization of biological tissue. The resulting device, called polarization-sensitive phase-shifting digital holographic microscope (PS-DHM), records in on-axis geometry the interference between the reference and object beams with the same polarization, but were acquired at two orthogonally polarizations. The object wave transmitted by the biological tissue and magnified by a microscope objective. CCD camera records the two resulting holograms at vertical and horizontal polarizations. The PS-DHM system was upgraded with the liquid crystal variable retarder to perform phase shifts in the reference beam. The polarization-dependent phase-shifted holograms are recorded by rotating the half-wave plates. Using a single hologram, we reconstruct separately the phase map at each polarization, which are used then to represent the phase difference at two orthogonal states of polarization. This phase difference reflects the polarization-dependent refractive index associated to the anisotropy of biological tissue under study. The reconstruction and least-square unwrapping algorithms are used to extract phase information of biological tissues at different polarization states. The birefringence of tissue is obtained from the above-phase distributions. The proposed method is illustrated with applications to three samples: the cancer cells hematoblast, the pollen cells and the heart tissue. The results show that polarization sensitivity exists in the cancer cells hematoblast tissue, the pollen cells itself are not the anisotropic, but their walls are birefringent, and any significant anisotropy in the heart tissue was not watched. These results will provide reference for clinic diagnoses and pathological research.

Cathodoluminescent UV-light (peaked at 315 nm and 355 nm) sources have been created using commercially available phosphors, with photocatalytic activity observed at irradiation of titanium dioxide. The power density of UV radiation is higher than 10 mW/cm2. The photocatalytic efficiency was estimated by measuring the oxidation rate of acetone vapors (reaction rate exceeds 2 ppm/min).

The paper presents a solution for a positioning device for urban life mobility improvement based on MEMS- INS and GPS data fusion. Two stages are used to process the MEMS-INS and GPS data. At a first stage, which runs off-line, the data fusion uses a method coming from the bio-signal processing domain, i.e. an extension of the Partial Directed Coherence (PDC) method. An optimized filtering procedure is applied here to the IMU components by using the wavelet transform, to process the inertial sensors signals. At the second stage, which runs online, a Kalman filter is used to fuse the INS and GPS data. Also, are shown the hardware structure of the system and the results of the system testing at the lab level.

Orthodontic stripping is used to reduce interproximal enamel tissue to solve aesthetic and occlusal problems. There is a wide variety of stripping instruments available on the market. In this study, a qualitative analysis was performed by means of scanning electron microscope with the aim of acquiring information about the efficiency of different manual, mechanical and optical enamel reduction techniques. The paper is especially dedicated to the in vitro use of the Er, Cr: YSGG laser for orthodontic purpose – an objective that has not been indicated and evaluated so far in clinical practice.

The clinical tests of device based on Metal Insulator Semiconductor Field Effect (MIS-FE) gas sensor for Helicobacter pylori infection diagnostics (HP-infection) are done by breath test method. This method is based on detecting increase ammonia concentration in patient’s exhaled air after reception of carbamide water solution. The device’s stable operation is based on MIS-FE gas sensor’s high sensitivity to ammonia, sensor’s parameters stability as well as especially developed two channels gas sampling system.

This article discusses how to build an inexpensive radiation identification device. The device can be used in the X-ray environment and can be a real-time indicator of large variations in ionizing radiation. The device is made of two compatible data acquisition boards, the main sensor involved is SBM-20-Geiger Muller. Current devices, such as photographic dosimeters or Geiger-Muller sensors, are not digital and do not alert quickly if there is significant radiation exposure. The device developed and presented in this article makes it possible to quickly identify and prevent ionising radiation. The device was calibrated using a Gamarad DL7 device, with a radiation source: Americium 241, by identifying the radiation level, the presented study was performed.

This article will identify some of the most advanced systems for identifying biomechanical parameters in the lower limbs and the entire human body.Technology has evolved, from here, we have devices such as Kistler plate, with which we can identify forces and accelerations in the limbs, FootScan plate, this device shows the plantar position, center of gravity-pressure of the human body, foot pressure and last but not least, the XSens device, with the help of which various biomechanical parameters can be identified. At the same time, the article offers a multicriteria analysis, through which we can realize the performance of the mentioned devices.

Advanced heart failure is an increasing prevalent pathology with important socio-economic impact, justifying the tremendous worldwide effort to develop and improve valuable alternatives to heart transplantation. Mechanically circulatory support is now into the spotlight with evidence showing improved survival and quality of life in an extremely fragile population. However, severe side effects such as thrombosis, bleeding or infection still limit its clinical use. Against this background, our multidisciplinary team (bioengineer, cardiologist, and cardiovascular surgeons) designed an innovative left ventricular assist device suitable for patients with advanced heart failure as bridge to cardiac transplant, temporary support when myocardial recovery is possible or as destination therapy for patient not eligible for heart transplantation. The device consists of an electronic circuit, internal battery, wireless energy receiving antenna and an axial flow pump that mobilizes blood from the heart to the arterial system, unloading the failing heart. The device is designed to provide multiple features: flow of blood with minimal turbulence and without areas of mechanical stress, energy autonomy and wireless power supply, possibility of fully implantation by minimally invasive techniques, and biocompatible amorphous tetrahedral carbon coating that may provide the premises to reduce the negative effects of known devices.

Rapid implementation of nanoobjects for biomedical applications needs simple techniques to characterize them. Great attention is paid to the surface of nanoobjects. Its electrical charge has a significant influence on the interaction of the nanoobjects with biostructures.The article reviews the fundamentals and applications of near-threshold electron emission spectroscopy to characterize and control the electrical charge deposited on the surfaces of nanoobjects.

Most of the data generated by monitors in a clinical setting represent time series data which can be visualized and subsequently used for decision making. This usually is the simplest part. A more challenging aspect is using this data for more complex task like machine learning with the same goal – computer assisted decisions. Within this challenge raw biomedical signal data need to be preprocessed before being passed to the machine learning algorithm. This can be done by a multitude of methods. A number of such methods comes from the field of Algorithmic Complexity and although of a promising nature, these particular methods are poorly explored yet. The current research presents an example of applying the Block Decomposition Method to data routinely generated by patients in a modern Intensive Care Unit. The final goal of a larger research, the actual research being part of, is building a system for early sepsis prediction.

The miniaturization of medical electronics in recent years, like electronics in general, provides new opportunities for creating miniature and subminiature monitoring systems that are capable of monitoring important human biophysical signals. In particular, to carry out long-term monitoring of parameters of cardiac activity.In this case, a wide field opens up for the development of new effective wearable devices. However, the circuitry implementation of such devices is impossible without significantly new methods of processing and analyzing such complex signals as the signal of the electrical activity of the heart. The paper proposes a study of the probabilistic properties of rhythmograms depending on the change in the patient's cardiac state. The results of these studies make it possible to obtain information about changes in the internal structure of the conduction of electrocardiographic impulses and significantly increase the information content of rhythmograms.

The brain-computer interface (BCI) constitutes an excellent solution for people with neuromotor disabilities that need an alternative communication and control channel with the outside environment. This paper proposes a Python-based BCI system for controlling a mobile assistive device using the NeuroSky EEG portable headset and the Raspberry Pi microcontroller board. Thus, disabled persons could enjoy the opportunity of controlling a mobile robot by using commands based on voluntary eye-blinking. The original implementation of the proposed BCI system consisted of Python programming for raw EEG signal analysis on the computer (Spyder IDE) for detection and counting of intentional eye-blinks and Python coding for executing the robot movement commands by the Raspberry Pi (Thonny IDE). The WebSockets protocol facilitates wireless communication between the computer (Windows) and Raspberry Pi. The presented BCI system is an experimental prototype for a better understanding of simulation and testing of the BCI technology by people with neuromotor disabilities.

Today, The World Health Organization estimates that by 2030, about 25 million people will die from cardiovascular disease every year, meaning that heart disease will remain the leading cause of death. One of the most common types of cardiovascular disease is arrhythmia caused by abnormal electrical activity in the heart. An effective method for studying the nonlinear characteristics of HRV on an ECG, in particular arrhythmias, is the Poincaré Plot - a diagram in which each R-R interval is displayed as a function of the previous R-R interval. This work is a continuation of studies of a modified graphical method for displaying HRV, called Speed Spot, in which both the current value of the rhythm and the rate of its change are graphically displayed. In particular, the asymmetry of the location of the points is interesting, which shows the degree of imbalance in the processes occurring in the heart. The paper considers asymmetry in each of the four quadrants of this graphical representation as a possible mechanism for detecting various arrhythmias.

With the rapid development of the world economy and the significant improvement in living standards, people’s average life expectancy has increased, which has led to substantial changes in the types of diseases encountered in the daily population. These diseases are found in both older and younger people. At the same time with the development of informatics in the field of health, the clinical data of the patients can be registered in different servers that are found under the name of Cloud. They allow the visualization and interpretation of recordings from subjects using a device connected to these servers, an important role for both medical staff because it can easily keep track of certain patients with chronic diseases.The system uses an Arduino development platform to purchase data from attached sensors. The ECG module is based on an instrumentation amplifier with several levels of filtering, so as to acquire a series of signals corresponding to a physiological chart in a single channel, which are sent to an Atmega microcontroller. The pulse detection part was performed using a pulse oximetry module and determines the levels of oxygen saturation in the blood.The advantages of this system consist in: efficient, fast acquisition and storage, real-time remote monitoring, user-friendly interface, accessibility for patients and caregivers.

Provided results of research for improvement of recognition accuracy of eyeballs and bone structures of the eye sockets. For the goal achievement was used deep learning of the neural network with and without use of augmentation. Shown, how expanding the training set improves neural network accuracy.

A model has been developed to describe the valence tautomeric transformation in a crystal containing as a structural element trinuclear complexes with electronic configurations Cr3+ –dhsq3−−low-spin Co3+ and Cr3+ –dhbq2−−high-spin Co2+ at low and high temperatures, respectively. The model takes into account the antiferromagnetic exchange coupling between the dhsq3−−ligand with the itinerant electron and the Cr3+ - ion, the ferromagnetic exchange coupling Cr3+ – high-spin Co2+ as well as the interaction of the Co-ion with the full symmetric breathing mode of the nearest crystal surrounding producing a strong localizing effect. In the model there are also accounted for the cooperative dipole-dipole and electron-deformational interactions. The parameters of the main interactions governing the observed phenomena are evaluated through DFT calculations. The interplay between the intracluster exchange coupling and the cooperative interactions has been demonstrated to lead to gradual and abrupt spin transitions as well as to those accompanied by a hysteresis loop. Within the framework of the suggested model a qualitative and quantitative explanation is given of the magnetic susceptibility of the [(Cr(SS-cth)(Co(RR-cth)( $$\mu - \text{dhbq})]\left( {\text{PF}_{6} } \right)_{2} \text{Cl}$$ μ - dhbq ) ] PF 6 2 Cl compound.

A model for the description of the charge transfer induced spin transition in a crystal containing as a structural element cyanide-bridged binuclear Co-Fe clusters is presented. The cooperative interaction responsible for the spin transformation originates from the coupling of the acoustic crystalline modes with the molecular vibrations of the nearest ligand surroundings of the metal ions. The developed model is applied for the description of the observed magnetic characteristics of the [{(Tp)Fe(CN)3}{Co-(PY5Me2)}](CF3SO3)·2DMF complex.

In the present study the course of spin transformation in the linear trinuclear [Fe3(bntrz)6(tcnset)6] complex, exhibiting a complete one step transition at T = 318 K, and in the tetranuclear protonated [Fe4(H6L4)]6+ and [Fe4(H8L)]8+ complexes is examined with the aid of DFT single point energy calculations. The suggested approach allowed to explain the peculiarities of spin crossover observed in the [Fe3(bntrz)6(tcnset)6] compound. The DFT study of the energy pattern of the tetranuclear [Fe4(H8L)]8+ complex at low and high temperatures revealed, that upon deprotonation of the complex the number of the FeII ions participating in the spin crossover transformation is reduced from two FeII ions to one.

High quality beryl crystals with D2O molecules in nanocages are synthesized and carefully characterized. IR mapping of the crystals showed drastically different concentration distribution of water-I and water-II molecules. The effect of water concentration on the dielectric properties of D2O@Beryl was systematically studied. Two areas of the crystal with same water-I concentration and highly different water-II concentrations were studied by temperature-dependent terahertz and impedance spectroscopy. The experiments reveal a strong dependence of the dielectric properties of the crystal on water-II concentration. The sample with low water-II content showed an anomaly at T = 2 K in the temperature behavior of radiofrequency permittivity; no saturation in the temperature-dependent behavior of terahertz soft mode is observed. These observations contrast with our previous results on incipient ferroelectricity in H2O@Beryl. We speculate about a possibility of new ground state developed in dipolar water lattice in beryl.

Optical spectra (absorption and reflection) of GaSe layered crystals were studied at room and low (10 K) temperatures. Contours of measured reflection spectra were fitted by help of dispersion equations. Photoluminescence spectra excited by 448 and 325 nm laser lines were measured at low temperatures. The observed features can be explained in the framework of model of the existence of Frenkel and Wannier-Mott excitons.

An initially excited two-level quantum-dot embedded on a quantum mechanical resonator is placed in an optical cavity. The quantum-dot has its transition frequency modulated by an off-resonant laser, which leads to a slow-down of the quantum-dot decay within the bad cavity limit. The effect of spontaneous emission control may be enhanced by considering various frequency modulation signals.

We study the dynamics of atomic-molecular conversion in ultracold gases of lithium isotopes. It is shown that the time evolution of atoms and molecules in the process of stimulated conversion is largely determined by the initial density of particles and the initial phase difference.

We discuss methods for synthesis and fabrication of photosensitive thin azopolymer films. Spectroscopy of films presents information as about nonactinic and recording wavelengths as a for refraction index calculations by Swanepoil method. Photoinducing of anisotropy was done by blue laser. The resulting polarimetric light parameters produced by photoinduced anisotropy measured at nonactinic He-Ne red wavelength. For this aim a polarimeter was applied. Kinetics of a value of photoinduced anisotropy, azimuth and ellipticity of light passed through films were investigated.

The fibroblasts are the most used cells for in vitro testing of various substances. The explant modality of fibroblast isolation is a widely used method. In order to fix the explant to the cell culture surface are used various substances or are performed various manipulations, such as applying the mechanical force or explant sticking to cell culture surface after a short period of drying. This paper presents another way of fibroblast isolation using the explant modality, which consists in manipulation with the volume of cell culture media in a well of a 12-well plate during several cycles of cell isolation. From 3 domestic rabbits, under general anesthesia, pieces of dermis were harvested and cutted to 32 ± 8 mm3 (n = 7), and placed by one per well, in a 12-well plate. For 3 days the explants were incubated in 3 ml of cell culture media to ensure the cellular multiplication on the explants. After removing the cell culture media, a small volume of medium was added to maintain the explants moist but fixed to the cell culture surface. When the explants self-attached to the cell culture surface, in the wells were poured 2 ml of cell culture media. After cellular colonies formation, the explants were transferred to another well in which the previous procedure was repeated, starting with the addition of a small volume of medium. The isolated cells from the wells, were cultured to a 80–90% confluence and subcultured in a 75 cm2 flask. As a result, at 16 ± 2 days, from the attached explants (n = 6), after isolated cells subculture to a confluency of 70–80%, were obtained 2.9 × 106 ± 1.6 × 105 cells per flask, which were identified as fibroblasts by Hematoxylin-Eosin and Masson Trichrome stainings.

Regeneration of articular cartilage is a major problem in the field of orthopedic surgery and regenerative medicine. Most research on cartilage regeneration performed on rabbits, tests the possibilities of cartilage regeneration on the non-weight bearing surfaces of the distal femur - in the trochlear groove of the femur, giving less importance to the weight bearing surfaces, the areas where the joint surface is subjected to various high forces. The study was performed on 4 month old domestic rabbits in which type I collagen sponges combined with bone marrow mesenchymal stem cells (MSC) were transplanted. For comparison, the combined grafts were transplanted at 2 levels - in a defect on the weight bearing articular surface of the medial femoral condyle (n = 3) and in 2 defects made in the trochlear groove of the femur (n = 3). As a negative control served the experimental defects (n = 2) made in the the trochlear groove of the rabbits femurs (n = 6). The results were evaluated using the Unified Histological Score of Regenerated Cartilage (UHSRC) after removing the animals from the experiment at 12 weeks, and the last 3 from the control group at 52 weeks. As a result, at 12 weeks no difference was determined between the control group and the combined grafts transplanted into the defects from trochlear groove (p > 0.8), but, a significant difference was found between results obtained after transplantation of combined grafts in the weight-bearing and non-weight-bearing areas (p = 0.002). The control group removed from the experiment from the experiment at 52 weeks has better results comparing to those removed at 12 weeks (p < 0.1).

More than 200 bones provide vital functions to the human body. The unique regenerative capacity of bone allows the healing without structural or functional impairment in case of minor defects, while in case of major defects, bone tissue engineering (based on a scaffold, cells and bioactive factors) can be seen as an alternative to the conventional methods. Composite scaffolds for bone tissue engineering based on biopolymers and ceramics, the main components of human bone, successfully combined the key properties of the two biomaterials, as is reported in the present paper. The inclusion of magnetite in the scaffolds brings also great advantages, and moreover, functionalized with drugs, will make possible its use as targeted drug delivery systems.

Decellularized matrices for tissue engineering seem to be an attractive material for providing biological vascular grafts for patients with advanced peripheral arterial disease who require bypass surgery, but do not have suitable autologous small-caliber vessels (˂6 mm diameter). Currently, a variety of decellularization (DC) techniques have been proposed such as physical, chemical, and/or enzymatic methods; however, identifying an optimal protocol resulting in preservation of favorable physiochemical properties of the vascular scaffold is still elusive.The goal of the proposed study was to examine the capacity of sonication to completely decellularize small-diameter blood vessels when applied alone, to test the effect of waves’ parameters on the processing quality and matrix microarchitecture preservation, and to evaluate the possibility to reduce the time required for cell removal when ultrasound is used in combination with non-ionic detergents.Contradictory to other DC protocols reported previously, we were not able to record completely or even partially cell removal in all studied groups. Interestingly, the combination of conventional chemicals, as Triton X-100, with physical method did not result in improving the DC efficiency and did not offer tissue permeabilization and easier chemicals access towards deeper tissue layers. In addition, when high sonication power was applied, significant destruction of the vessel matrix was determined. In summary, the use of sonication had no beneficial effect on DC in this study.

Cell-encapsulating hydrogels must be obtained in rigorous and completely cytocompatible conditions, offering this way tissue engineered products that mimic the in vivo microenvironment. These hydrophilic structures bring in vitro testing to a new level of complexity by offering a tissue-like architecture. Various polymeric structures have been studied in the aim to build hydrogels with physical and mechanical integrity as cell-supporting medium. In this study, collagen-based hydrogels crosslinked with oxidized polysaccharides (chitosan and hyaluronic acid) were used for encapsulating two different types of cells, primary Albino rabbit fibroblasts and human epidermoid carcinoma A-431 cells. The cells were able to proliferate into hydrogels and maintained their viability for at least eight days, for both cell lines and initiate tumor formation in the case of A-431 cells. It was observed a better cell integration into oxidized hyaluronic acid crosslinked hydrogels which allowed cell-cell interactions and the formation of spheroids.

Polymeric hydrogels are soft and hydrophilic materials of great interest for the engineering of soft tissues, as mimicking structures of the extracellular matrix; because of their 3D architecture and biological properties constitute an adequate environment for cells function. Biopolymers like collagen and hyaluronic acid have a good biological response but the mechanical characteristics make necessary the crosslinking of the networks in order to build resistant and easily workable structures. The paper presents preparation of new hydrogels based on methacrylated collagen and methacrylated hyaluronic acid/hyaluronic acid as natural-based networks with controlled morphology and biointeractivity. FTIR spectra confirmed the proposed structure and the scanning electron microscopy data indicated a porous morphology dependent of the ratio between polymers. The prepared hydrogels are highly swellable, bioadhesive and degradable by enzymes. In vitro cytotoxicity tests revealed a very good material response in contact with cells (fibroblasts).

Currently available data have a major impact on widening the applications area of zinc oxide (ZnO) and gallium nitride (GaN) nanoparticles (NPs). Being a new medical domain, nanomedicine shows a spectacular growth of published works. Thus, in this paper we aimed to provide comprehensive current information on the implementation of inoffensive synthetized ZnO and GaN nanoparticles. The articles in the PubMed database, Bethesda (MD): US National Library of Medicine, “PubMed.gov”, Google Scholar Academic containing the keywords “nanoparticles, zinc oxide, gallium nitride, cytotoxicity, adhesion” were selected. From these articles it was collected and processed the information related to the applicability of ZnO and GaN NPs. Nanoparticles based on ZnO and GaN currently have a wide range of implementation in the field of oncology, antibacterial, antifungal domains. The combination of ZnO and GaN nanoparticles as adjuvants in target factor treatments shows an increased efficacy of the active substance obtained by ecological methods. The application of ZnO GaN NPs requires innovative methods to obtain beneficial results in biomedicine. Possession of clinical nomenclature for use of ZnO and GaN NPs would reduce their cytotoxic effects in practical applications.

The paper proposes a new device for remote healthcare. This device is intended for elderly patients with cardiovascular disease who are living alone. The advantage of the device is that it can be used 24/7. The device has simple and understandable interface. The design of the device is based on two modern technologies, they are modern infocommunication technologies of LTE networks and technologies of flexible electronics. Also, this device can be used for remote healthcare during the COVID-19 pandemic.

The uptake of gold in different tissues of female mice and their offspring after prolonged oral administration of gold nanoparticles to the females during pregnancy and lactation was investigated. Gold content in different organs was determined using neutron activation analysis. The highest content of gold was accumulated in kidneys followed by liver, lungs, blood and brain. Accumulation of gold in brain confirms ability of nanoparticles to pass through placental and blood-brain barriers. The average specific mass content of gold which crossed the blood-brain barrier was 3.8 ng/g (for female) and 1.1 ng/g (for offspring). The results are important for research on developmental and reproductive toxicity and safety of nanomaterials.

The devices and tools used in the cornea sampling and processing is and will be one of the requirements used by the Eye Bank. Technological and informational progress tends to modernize all types of the devices that lead to increased quality of the cornea giving a longer storage with the of the viability of all epithelial corneal layers, stromal and endothelial. Bioreactors are complex devices that maintain the storage of the cornea ex vivo that are closer to the physiological norm. Many studies show that the materials that are made of these devices directly or indirectly influence the activity of the cells.

Regeneration of the endodontic tissues shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Different natural, biological extracellular matrix could be used as scaffolds for tissue regeneration. This study is dedicated for investigation of the characteristics of decellularized dental pulp from extracted wisdom teeth and evaluated whether it could mediate pulp regeneration. Decellularized dental pulp represents a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases.

Individuals with borderline personality disorder (BPD) are more likely to experience pain and assess the pain as more severe than individuals with other personality disorders. Actual study researched psychophysiological reactivity of subjects with BPD by studying the breathing pattern and pain test. The study proceeded in two stages: first stage - psychometric testing using Personality Inventory for DSM-5 (PID-5; DSM-5 - Diagnostic and Statistical Manual of Mental Disorders); second stage included recording the parameters of the breathing pattern in resting state and pain test by compression of the middle third of the left shoulder. Time parameters of breathing pattern were significantly different between groups, unlike volume parameters. Pain test produces changes in breathing parameters in both groups, but in different way. Pain test appears to be a valuable method to detect psychophysiological changes in patients with BPD.

Zinc thioindate and gallium thiogallate single crystals were grown by a chemical vapor transport method. The cathodoluminescence and X-ray luminescence spectra of ZnIn2S4 and CdGa2S4 single crystals were studied. From cathodoluminescence spectra of ZnIn2S4 at low temperatures the forbidden gap width of (2.96 ± 0.02) eV at 80 K and optical depth of the deep acceptor level EA = (EV + 0.30) eV were determined. In the X-ray luminescence spectra of CdGa2S4 a single emission band is observed with an energy maximum at 2.14 eV and a slope within the high-energy range at approximately 2.34 eV identified as optical transitions of donor-acceptor type.

Pseudomonas aeruginosa is one of the most dangerous superbugs and is responsible for both acute and chronic infection. Current therapies are not effective because of biofilms that increase antibiotic resistance. Biofilm formation is regulated through a system called quorum sensing, and includes transcriptional regulators LasR and RhIR. These regulators are activated by their own natural autoinducers. Targeting quorum sensing is a promising strategy to combat bacterial pathogenicity. Flavonoids are very well known for their antimicrobial activity and inhibit Pseudomonas aeruginosa biofilm formation, but the mechanism of action is unknown. In the present study, we analyze the mode of interactions of LasR with taxifolin. We use a combination of molecular docking, molecular dynamics simulations to study the interaction of LasR with taxifolin. We show that taxifolin has two binding modes. One binding mode is the interaction with ligand-binding domain. The second mode is the interaction with the “bridge”, which is a cryptic site. Biochemical studies show hydroxyl group of ring A in flavonoids is necessary for inhibition. In our model the hydroxyl group ensures the formation of hydrogen bonds during the second binding mode. This study may offer insights on how taxifolin inhibits LasR and the quorum sensing circuitry.

We report in this paper the results of theoretical investigations of the dynamical properties of a laser with incorporated Distributed Brag Reflector (DBR) section under the influence of external optical feedback . The adapted Lang-Kobayashi model was used to simulate and analyze the dynamics of the considered laser device. We have identified the nature of the bifurcations that occur in such a system. We plotted the Hopf bifurcation, responsible for instabilities, in the plane of different parameters. The conditions that are necessary for stable laser operation are identified. We also demonstrate the influence of the length of active region on the stability of devise emission, and show how this property is changed by variation of detuning of the mode of solitary laser.

From the point of view of data engineering, the application of machine learning methods in the case of data represented by multivariate multimodal time series is a difficult task, but with a possible practical potential, which is insufficiently explored.From a medical point of view, the conditions described by this type of data are current problems in medicine, especially in anesthesia and intensive care and particularly in case of sepsis. The early diagnosis of life-threatening conditions can lead to increased treatment success, reduced mortality and reduced cost of care for this group of patients, especially in complex cases.This paper describes a research focused on identifying the most appropriate machine learning algorithm to be used for further investigations. It presents some results concerning the preclinical stage in developing of a machine learning system for early sepsis prediction with an anticipated potential of improving the clinical management of patients with sepsis.

Faced with the restrictions imposed by the Covid-19 pandemic, universities, as providers of higher education, have been forced to provide their students exclusively through a digital interface. For this, the institutions were challenged to select resources and platforms to support online education. The World Health Organization (WHO) advocates for research focusing on the impact and prediction of post-Covid evolution on education, in order to obtain adequate explanations for these challenges. The Technical University of Moldova (UTM) is the only technical higher education institution in the Republic of Moldova. TUM invests continuously in information technology infrastructure, as well as in the digital education of both students and academics. The aim of the study is to evaluate the university potential, from the perspective of digital technologies, in providing now, but also in the future, e-Learning. The most dominant form of providing learning content to TUM, during the pandemic, was online lectures via real-time video conferencing, which is confirmed by the continuous increase in the number of active MTeams users. And e-Learning did not negatively influence students’ learning. The obtained results show that TUM has demonstrated its potential to ensure the continuity and good development of the teaching process during the pandemic, maintaining the good quality of studies.

Nanotechnology has demonstrated performance in top technologies of the 50s-60s of the XX- century such as nuclear, cosmic and other domain. Although the first results were promising, the crucial point for further development took place later in 2000 with the adoption by the US of the National Nanotechnology Initiative (NNI) [1]. This served as an impetus for third countries that have adopted similar programs or strategies (EU member states, the Russian Federation, etc.) [2, 3]. Today, nanotechnologies are an indispensable component of the 4th industrial revolution, which radically changes the world. Nanotechnology is considered as a new frontier of engineering and research with an unimaginable long-term potential impact, giving rise to new interdisciplinary fields of research, engineering and education. Unfortunately, like any cutting-edge technology, it can also lead to the development of a new destructive technologies, especially of weapons of mass destruction (WMD). Therefore, risk assessment becomes critical in the context of dual-use technologies.This can be achieved only through joint efforts and consensus of the governments, researchers and large producers, and requires long negotiations. We find that a promising solution would be by regulating this domain at a national level, as well as via a Codes of Ethics for professional societies. The implementation can be initiated with a new University course covering the responsibilities of engineers and researchers in the preventing proliferation of WMD via nanotechnology and nanoscale science. This path has been followed by the Technical University of Moldova by developing a new curriculum in engineering and non-proliferation culture for master degree study.

As a rule, ions of some heavy metals are always found in natural and waste waters. The purpose of this work was to study the sorption properties of carbon material obtained from secondary raw materials (hazelnut and walnut shells) according to the technology we have developed; determination of its applicability in the purification of drinking and waste water, in which ions of several heavy metals are simultaneously present. The salts of lead, cobalt, iron and cadmium, as the most important pollutants of the water basin, were the adsorbates.Studies of solutions of various concentrations of metal ions showed that in the presence of all four ions, the maximum adsorption rate and the degree of extraction are achieved at a solution concentration of 0.0025 M Me+2 in 30 min, as for the effect of pH on the degree of sorption, the experimental results showed that the best values are achieved at pH 3 for cobalt ions and pH 3 ÷ 5 for copper, lead and iron ions.It was found that the nature of sorption by these absorbers is the same: for a given metal, hydrated ions are adsorbed in the same way on different absorbers.The larger the crystal radius of an ion with the same charge, the better it is adsorbed (sorption capacity for Pb++ ions is maximum, and minimum for Co++ ions).

There is a lot of data confirming the effect of microwave radiation on psychophysiology and human health. The paper considers a method and a measuring and information system for dynamic monitoring of microwave environmental pollution in cities. It is assumed that a fully implemented system will consist of thousands of portable personal devices – mobile terminals held by volunteers who move around the city in their usual life and, possibly, a number of city vehicles will be equipped with such terminals. The structure and features of the technical implementation of the proposed distributed, non-deterministic system, which allows real-time mapping of the microwave dose load of the city population, are considered. The personal terminal records the geographic position using a GPS navigator as well as the basic parameters of microwave dosimetry. The data are transferred to a web server where they are stored in a cloud database. From there, they can be transferred to the environmental and medical services of the city, and they can also be read and displayed in a convenient form on any device with access to the corresponding Internet resource. The results of testing a prototype of the system when acquiring data on one of the routes in the city of Moscow are presented.

The uses of Terahertz (THz) radiation are broad, ranging from scanning packages to identifying various chemical compounds. Its effects on living matter have been neglect. The scientific literature available to date describes various effects on living matter depending on the type of cells studied. No studies thus far have investigated the effects of THz radiation on dormant seeds, whose animal-like metabolism creates a unique opportunity to assess the full extent of THz radiation as well as further analyze the mechanism of action behind this type of non-ionizing radiation. The aim of this study is to assess the radiation’s effects on the sprouting of wheat seeds. Previous studies have shown a positive effect on the growth and proliferation of plants when placed under the effects of THz radiation; however, due to the aforementioned unique metabolism of seeds’ cells, the ongoing hypothesis is that the seeds will suffer under the effects of the THz radiation. The seeds have been placed into two distinct batches, depending on whether they were exposed dry or wet. Multiple time-frames were assessed to different sub-groups, having one control sub-group in each batch. The exposed seeds saw a significant decrease in the success of germination, albeit the fact that those that survived saw a significant increase in their growth rate without any subsequent exposure. More research is needed to assess the effects of THz radiation on seeds, but the technology seems promising for use in agriculture, especially seeing the daunting effects of climate change on crop yields.

Presented observational data indicate that a significant number of infections with the SARS-CoV-2 coronavirus occur by air without direct contact with the source, in addition, in a tangibly long time interval. It is noticed that atmospheric precipitations help to cleanse the air from pollution and at the same time from viruses, reducing non-contact infections. These facts additionally actualize the problem of optimal microbiological decontamination of air and surfaces. In order to optimize microbiological sterilization, a thermodynamic approach is applied. It is shown that irreversible chemical oxidation reactions are the shortest way to achieve sterility, they being capable of providing one hundred percent reliability of decontamination. It is established that oxygen is optimal as an oxidant, including ecologically, because it and all of its reactive forms harmoniously fit into natural exchange cycles. The optimal way to obtain reactive oxygen species for disinfection is the use of low-temperature (“cold”) plasma, which provides energy-efficient generation of oxidative reactive forms - atomic oxygen (O), ozone (O3), hydroxyl radical (⋅OH), hydrogen peroxide (H2O2), superoxide (O2−), singlet oxygen O2(a1Δg). Due to the short lifetime for most of the above forms outside the plasma applicator, remoted from the plasma generator objects should be sterilized with ozone (O3), the minimum lifetime of which is quite long (several minutes). It is substantiated that microwave method of generating oxygen plasma is optimal for energy efficient ozone production. A modular principle of generation is proposed for varying the productivity of ozone generating units over a wide range. The module is developed on the basis of an adapted serial microwave oven, in which a non-self-sustaining microwave discharge is maintained due to ionizations produced by radionuclides-emitters.

Phenothiazine based compounds are well known for their successful application in bio-medicine. Used for many years for the synthesis of many classes of drugs, in the last two decades the phenothiazine derivatives proved a promising potential for the cancer treatment. Taking into account phenothiazine properties and poly(ethylene glycol) biocompatibility, a series of three new PEGylated phenothiazine derivatives were prepared by grafting PEG chains to the phenothiazine core. The structure of the targeted molecules was confirmed by FTIR and NMR spectroscopy. The capacity of the synthetized compounds to self-assembly in water was studied by DLS and UV-vis techniques. Their biocompatibility was assessed on normal human dermal fibroblasts and five human cancer cell lines. The synthetized compounds proved excellent biocompatibility on normal cells. A concentration dependent cytotoxicity against cancer cell lines was noticed for two of synthesis PEGylated phenothiazine derivatives. In vivo anti-tumor investigations presented high tumor inhibition comparable to traditional drugs.

Being a family of biodegradable materials with natural origin, melanins are widely used for development of model bioelectronic devices. However, the mechanism of their electric conductivity is still a matter of discussions.Current study is devoted to the room temperature impedance measurements of pure and copper-doped synthetic eumelanin at different values of humidity in frequency range 0.1–5 $$\cdot$$ · 106 Hz. To analyze the obtained impedance spectra, we utilize density relaxation times (DRT) methodology. The performed analysis demonstrates an absence of significant difference in relaxation times in the studied materials. At the lowest frequencies, the doped material has about 30 times lower conductance than pure material. Possible origins of the observed phenomena are discussed in terms of copper ions activity as complexing agent for water molecules and semiquinone groups of melanin.

A possibility of nanostructuring protein systems is demonstrated based on whey electroactivation. Whey as a raw material is not only a valuable by-product available in most of the cheese-production industry areas, it is also relatively cheap, with high nutritional value and several functionalities, with unique properties, which allows the study of nano-sized structures of whey proteins. Various non-uniform isolations of protein fractions in the protein-mineral complexes (PMCs) at the electroactivation of the studied whey is determined, first of all, by the properties of each fraction separately and by their behavior at the electrochemical action. The experimental data on the isolation of Beta-Lactoglobulin (β-Lg), the most abundant whey protein, are presented; the aggregation of β-Lg in the PMCs via various mechanisms and modes has been presented by the authors earlier. The isolation of Alpha-Lactalbumin (α-La) in the PMCs upon the electroactivation of whey differs from the isolation of β-Lg in the PMCs. Electroactivation of whey allowed the formation of high molecular weight protein compounds. Three fractions of casein: ‒α-CSN, β CSN, and κ-CSN, with a molecular weight of 37, 33, and 46 kDa, respectively, were identified. The electroactivation of whey and the extractions in the PMCs ennobled with certain protein fractions allowed to specify different sedimentation and isolation mechanisms of the whey proteins: the formation of a calcium phosphate caseinate complex; salinization of proteins; and sedimentation of proteins in their isoelectric point.

Silver nanoparticles (AgNPs) are one of the most actively used nanomaterials. Therefore, their release into the environment becomes inevitable. Consequently, studies regarding the harmful effects of AgNPs towards organisms are very common. In the process of investigating the effects of silver nanoparticles on living cells, other effects besides the toxic ones were revealed. Thus, different nanoparticles can stimulate biosynthetic processes, which will significantly expand their application in biotechnology. The aim of this paper was to elucidate the possibility of using small silver nanoparticles (10–20 nm) stabilized with polyethylene glycol and citrate as stimulators in the biotechnology of microalga Porphyridium cruentum. This red microalga is recognized as a producer of polysaccharides, proteins, polyunsaturated fatty acids. Silver nanoparticles stabilized with polyethylene glycol of 12 nm in size, as well as nanoparticles stabilized with citrate of 10 and 20 nm in size, were used in concentrations ranging from 0.01 to 1.0 μM. Concentrations were determined for each type of particles, where an increased accumulation of polysaccharides and proteins was observed in Porphyridium cruentum biomass. Moreover, the lack of toxicity of these nanoparticles was confirmed by maintaining a high level of productivity.

The COVID19 pandemic that terrorizes the world with terrible aggression calls for the urgent finding of tools that would quickly inactivate viruses in the environment to reduce the chance of aerosol infection and contact transmission. For the inactivation of SARS – CoV – 2 viruses we used LEDs with maximum emission on the wavelength 255 ± 5 nm. All sources of UVC bactericidal radiation have emission peaks close to the center of the DNA and RNA absorption spectrum and may underlie devices and therapies to disrupt the spread of infection.We studied the inactivation of SARS – CoV – 2 viruses by annihilating the structural components of the viruses that manifest in the amplification process in the PCR procedure.

In this paper, the prospective of using organic nanostructured crystals of p – type TTT2I3 (tetrathiotetracene-iodide) and n – type TTT(TCNQ)2 (tetrathiotetracene-iodide-tetracyanoquinodimethan) as components of thermoelectric biosensors is investigated. A thermoelectric biosensor consists of a p-n module, specially designed to be used as power generator, converting human body heat into small electrical signals, or as local cooler, able to create low temperatures (up to $$- 20^\circ {\text{C}}$$ - 20 ∘ C ) on small surfaces. In biomedical applications, the temperature gradients are low and, in order to obtain as much as possible high electrical signal, materials with enhanced thermoelectric properties are required. Organic crystals of TTT2I3 and TTT(TCNQ)2 were investigated earlier and it was established that these organic compounds are prospective thermoelectric materials if an appropriate optimization of carrier concentration with further purification of the crystal is performed during synthesis. In the following, the electrical conductivity, thermopower (Seebeck coefficient) and the delivered voltage from a p-n module constructed from the mentioned crystals are calculated for different crystals parameters at room temperature. It is established that a single p-n module made of organic crystals can deliver up to 5 mV under a temperature difference of 20 K around the room temperature if optimization procedures are applied.

An idea of a sensor of direct magnetic fields using the magnetoelectric effect in a planar ferromagnetic-piezoelectric composite structure is described. It is shown that introduction in the sensor circuit a negative feedback, which contains a current amplifier, a convenient approximation characteristic former, and a compensation coil, results in a widening of the sensor magnetic field region without of linearization of its characteristic. The approximation nonlinear characteristic is close in shape to the original sensor characteristic. Therefore, no deep negative feedback is required and thereby stability is ensured. As this convenient characteristic, a fractional-quadratic relationship is used, for which an invariant is performed between the output voltage value and the magnetic field strength. Such an invariant is a cross ratio (double proportion) for four values ​ ​ or samples of these values. The cross ratio contains the differences of these values ​ ​ and the ratios of these differences. Therefore, additive and multiplicative errors of the output voltage measurements due to the accuracy of the measuring instrument, the noise of the sensor itself and the electronic circuit are mutually reduced.

A fast responding NO2 sensitive device operating at room temperature has been realized using the nanolayered amorphous Te (a-Te) grown onto insulating wafer of silicon dioxide (SiO2) between Pt contact electrodes with larger thickness in a planar arrangement. The structure of the fabricated sensor has been investigated by AFM and SEM but its characterization was realized via studying the current - voltage characteristics, dynamic response, long – term stability and effect of humidity. Explanation of obtained results is given in terms of a model based on simultaneous involvement of contact and surface phenomena for the gas sensing. As the Pt electrode work function (5.43 eV) exceeds the respective value of a-Te (5.03 eV) the ohmic contacts are formed and the current flow is controlled exclusively by bulk resistance of a-Te nanolayer that is known to be controlled by type and concentration of toxic gas of the ambiance. Wherein, as the energetic forbidden gap of a-Te (0.33 eV) is less than the work function difference between contacting materials, at the contacts can arise the degenerate regions of p-type metallic Te, as well as geometric contact gaps originated from microscopically roughness. The gas adsorption inside these contacts gaps leads to increasing the portion of the semiconducting a-Te nanolayer turned into metal of p-type Te and consequently to a fast increasing of the current.

This review paper briefly analyzes the history, development trends, current state of the sensors’ developments based on micro-and nanotechnologies for medical and biological research. The classification of such sensors is presented; their design and technological features and applications are considered.

Interpenetrating composites are an advanced class of engineering materials where two continuous phases form complex three dimensional interconnected networks. In contrast to traditional composites they can exhibit a variety of advantages such as isotropy and improved coherence between the constituents. In this work the advantages of soft interpenetrating composites made from polymers are explored. A strong interaction between the two phases is found, increasing the compressive modulus of the composite by at least a factor of 2 compared to the unfilled matrix. This increase in stiffness is found in all directions. An additional anisotropy can be introduced by compression of the foam like framework structure prior to infiltration of the soft silicone matrix. Tailoring the stiffness in such a way has promising applications e.g. in artificial cartilage.

Biocompatible hydrogels were synthesized from chitosan and 2-formylphenylboronic acid (2-FPBA), by the acid condensation reaction of chitosan’s amine groups and aldehyde group of 2-FPBA. FTIR and NMR spectroscopy demonstrated that the hydrogelation is a consequence of the formation of reversible imine linkages between the reagents, while wide angle X-ray diffraction proved the highly ordered supramolecular architecture of the obtained hydrogels. The viscoelastic behavior of the hydrogels was evaluated by rheological measurements, performed at human body temperature. The hydrogels were highly elastic, stiff and strong, with a quite high resistance to deformation and a high recovery degree. The morphology investigation by scanning electron microscopy revealed the samples’ porosity, forming sponges-like microstructures, with quite uniform pores size distribution. The antifungal activity of the synthesized hydrogels was evaluated on two Candida strains and the obtained results recommend these materials for the treatment of Candida infections.

In this study, the terahertz-infrared spectra of extracellular matrix and filaments of S. oneidensis bacteria, bovine heart cytochrome c and bovine serum albumin were examined by means of Fourier-transform infrared spectroscopy technique. The absorption lines of water and aqueous cations hydronium H3O+  and Zundel H5O2+  were detected, of the highest intensity in the bacteria extracellular matrix and filaments samples and of the lowest intensity in the albumin samples. We demonstrate that there exists correlation between spectral signatures of aqueous cations and charge transport signs in the investigated materials, which sheds light on the mechanisms of charge transfer.

In this paper we demonstrate the fabrication of a SERS detector based on GaN ultrathin membrane. The GaN membranes are elaborated by the so-called Surface Charge Lithography approach. The obtained membranes are functionalized by 20 nm Au nanodots and characterized by different tools in order to demonstrate the material quality and sensitivity enhancement for Rhodamine B detection in the micromolar range.

ZnO:Ga:Cl ceramics were sintered using chemical vapor transport technique. Ga content was varied in a range of 0−10 mol %. The wettability of unpolished and polished surface of ZnO:Ga:Cl ceramics was investigated. The polished and etched surface of ZnO ceramics is in a hydrophilic state. The presence of Ga impurity leads to a strong increase in the water contact angle to 131°. This behavior is attributed to a high concentration of free electrons, which suppress the formation of intrinsic surface defects acting as traps for water molecules. Air pockets on unpolished surfaces of ZnO:Ga:Cl ceramics are an additional factor that increases the water contact angle.

Local use of wound dressings still remains an important element of comprehensive wound treatment. Materials capable of dosing the release of drugs, including antimicrobial action, are of the highest priority. The use of composite polymers with antimicrobial properties in low-intensity current without external power supplies can enhance their effectiveness in combating wound infectious agents and improve the results of wound healing in general.Therefore, the aim of our study was to investigate experimentally the antimicrobial action of a polymeric material based on poly(2-hydroxyethyl methacrylate), modified by creating a porous structure and saturated with antiseptic against strains of gram-negative microorganisms P. aeruginosa and A. baumannii in low-intensity current without external supplies.A composite polymer material was synthesized by the method of free radical thermal polymerization of a mixture of liquid monomer 2-hydroxyethyl methacrylate, crosslinking agent triethylene glycol dimethacrylate and polymerization initiator azobisisobutyronitrile. Additionally, distilled water as a pore-forming agent and the antimicrobial agent decamethoxine were added. Suggested composite without an antimicrobial agent, as well as existing materials of synthetic and biological origin that are widely applied for the treatment of wounds were used for comparison. Some of the materials were pre-immersed in 0.02% solution of the decamethoxine. To ensure the action of biogalvanic current, a special device was placed alternately on each of the tested samples. Determination of antimicrobial properties was performed by diffusion method on a dense nutrient medium.The results of microbiological research allowed to establish the advantages of the suggested material in combating the growth of gram-negative microorganisms A. baumannii, P. aeruginosa in vitro, as well as the feasibility of its use under conditions of low-intensity current without external power supplies.

The article publishes in vitro tests of the antibacterial and antifungal properties of new coordination compounds of Cu(II), Ni(II) based on ethyl 4-benzoate thiosemicarbazons derivatives of salicyl aldehyde. Two Gram-positive strains were taken as reference strains: Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 11778; two Gram-negative strains: E.coli ATCC 25922 and Acinetobacter baumannii BAA-747; three fungal strains: Candida albicans ATCC 10231, Candida krusei ATCC 6258, Cryptococcus neoformans CECT 1043. The best results were recorded at {Ni(HL1)Cl} complex, a selectivity is observed on Cryptococcus neoformans, with CMI = 0.016, CMF = 0.031 mg/mL and is twice as active as the control substance Nystatin. The purity and structural formula of synthesized compounds was confirmed by thin layer chromatography; IR spectroscopy; 1H, 13C Nuclear Magnetic Resonance Spectroscopy, metal analysis and magnetochemical analysis.

Titanium alloys have great applications as biomaterials due to their high mechanical strength and density ratio, good corrosion resistance, and biocompatibility. Type β alloys have aroused enormous interest in the development of biomaterials due to their low elastic modulus. This new class of alloys has been formed mainly by adding tantalum, molybdenum, proven not to have biocompatibility. Tantalum is an alloy hardening element, which can increase the mechanical strength of the material. At the same time, molybdenum is a strong β-stabilizer, stabilizing the β phase with 10% quickly. In this work, Ti-15Mo-xTa system alloys were produced by the powder metallurgy method. The result shows the prepared alloy presented the β-phase grain structure, showing more excellent mechanical properties than pure titanium due to hardening in solid solution.

In this paper we present the evaluation results based on the model for cyber security maturity assessment upon the cyber security program development for critical infrastructures (CI) in Republic of Moldova [1]. During last year the healthcare domains has become a target of strategic interest amongst cyber criminals. These events can lead not only to security breaches, but also to safety events that affect human lives. The findings confirm the recommendations of previous case studies on evaluation of cyber security requirements for healthcare inclusive nuclear and radiological domain. Therefore, we classify the results based on the dimensions of the recently developed Model for Cyber Security Maturity Assessment in CI [1]. The proposed model focuses on four primary dimensions: policies and administration, education and training, work environment, cyber risk management. It has been developed with the goal to help decision makers analyze the efficiency of information systems used for cyber risk management. The model is multidimensional and can also show the actual state of cyber security maturity in an organization, fact which was also proven by external reviews. The experimental test of this analysis confirm the applicability of the Model for organizations at different stages of cyber security development, as well as from different domains.

The methods of disease remote diagnosis, including the use of diagnostic video information, are becoming more widespread with the development of telemedicine technologies. At the same time, in modern systems of telemedicine video diagnostics, special requirements are imposed on improving the accuracy, reliability, efficiency, and quality of the received video information. The authors consider new approaches in telemedicine diagnostics technologies by digital data visualization using the example of video monitoring of a patient’s condition with atopic dermatitis.

The Brain-Computer Interface (BCI) is a challenging research field reporting outstanding breakthroughs in biomedical engineering. This paper proposes a new BCI research-related solution by implementing customized Python scripts based on an artificial neural networks model to classify the raw electroencephalographic (EEG) signal detected by the embedded biosensor of NeuroSky portable headset. Achieving this aim is possible by applying features extraction techniques on the raw EEG data to generate the training dataset composed of 3000 recordings corresponding to executing simple, double, or triple voluntary eye-blinks. Detection of their specific EEG patterns resulted in calculating the following seven statistical features: mean, median, standard deviation, route mean square, the sum of values, Kurtosis Coefficient, and skewness. The voluntary eye-blinking proved to be the most precise and easily detected control signal in a BCI application to assist people with neuromotor disabilities. The proposed Python implementation of BCI software is practical, especially for the initial stages of research, by leveraging simple to use, inexpensive, and efficient instruments.

This paper presents the development of a low-cost platform in the field of telemedicine, which can be used to monitor people suspected of being infected with SAR-COV-2. The platform was developed and tested at the Medical Engineering Laboratory of the Transilvania University of Brasov. The first part of the paper is dedicated to the importance of the research topic and the concept of telemedicine. The second part presents the main hardware elements that are used to make this platform. The last part presents the results and conclusions related to the operation of this platform.

The creation of specialized medical and diagnostic complexes for remote monitoring is currently identified as one of the promising areas of health care structure modernization. However, the efficiency of such complexes directly depends on the telemedicine techniques used, the socio-ethnic characteristics of their location and the general number of patients per unit of time. This paper is analyzed the techniques for remote monitoring of cardiovascular diseases which are necessary for the purpose of their optimal software and hardware support.

The paper presents a very simple system for locating and tracking an object/person moving outside a predetermined area, ensuring the transmission of information about the target position through mobile networks. It is highly adaptive to various uses by programming for different areas of action depending on the nature of the target movement - the size of the movement area, the speed of movement, etc. With the help of the device, it is possible to make a location with satisfactory accuracy. Location identification uses common, widespread applications: sending SMS, using Google Maps and Google Earth.

The Romanian version of the Medical Office Survey on Patient Safety Culture (MOSOPSC) of the US Agency for Healthcare Research and Quality has been applied for the first time in primary care centers in the Republic of Moldova. The aim was to assess the current status of patient safety culture and then identify strengths of it and areas for improvement.A cross-sectional study was carried out as part of the IRIS-2 international project on patient safety culture, which also involved Romania and Italia. Data collection in the Republic of Moldova started in February and ended in June 2020. The survey was distributed on paper and via email to a convenience sample of 820 family doctors and 93% of them volunteered to complete and return it. Half of the respondents were from the capital of the country (Chişinău).The 38 items of the section C-F of the survey were grouped in 10 composites measuring the patient safety culture. Percent positive response was computed for each item and dimension. The percent positive responses (PPRs) per item ranged from 35% to 100% and per composite from 41% to 97%.The highest developed patient safety culture areas (PPRs > 75%) were: Organizational Learning (97%), Teamwork (95%), Patient Care Tracking/Follow-up (90%), Staff training (87%), Overall Perceptions of Patient Safety and Quality (87%), Office processes and standardization (81%), Communication About Error (81%), Owner/Managing Partner/Leadership Support for Patient Safety (78%). The most critical area was “Work pressure and pace” (41%), while “Communication Openness” (74%) area was between.In conclusion, although most composites measuring patient safety culture from the point of view of family doctors in the Republic of Moldova showed areas with high development, there is room for further improvement, especially for the “Work pressure and pace” area.

Despite the spread of SARS-CoV-2 infection, knowledge of the symptomatology, modalities of transmission, severity and prognosis is limited. Based on the complex analysis of the 701 pediatric cases, from 5 public medical-health institutions in the Republic of Moldova, positively diagnosed with SARS - CoV-2 infection by the RT-PCR molecular method, 73% of the children were in close contact with a COVID-19 positive person in the last 14 days until the illness. Most of the hospitalized children develop moderate clinical forms of COVID-19 (84.17% cases). The mean age of children with severe form is lower compared to those with moderate or mild form. The sex of patients does not influence the course of the disease. Children's age influences paternal manifestations: children of preschool age (<7 years) more often show high fever, changes in consciousness, drowsiness, rash, diarrhea and dyspnea, while children > 10 years: headache, pharyngitis, hypo/anosmia, ageusia, myalgia, arthralgia and vertigo. No statistical correlations were found between the form of the disease and the presence of comorbidities. The evolution of pediatric COVID-19 infection is favorable, considering that 97.57% of children do not show clinical manifestations at discharge. Knowledge of various clinical pictures of infection with the SARS-CoV-2 virus would allow the doctor to make an early diagnosis, administer adequate treatment and establish preventive measures.

A review of published data sources, their synthesis analysis, a description of the developed approach in health-forming technologies, based on the use of natural physical environments of living, daily working and servicing activity, inducing adaptive plastic transformations, optimization of gas-energy exchange in the body, strengthening of sensorimotor integration. Strategically, the development is aimed at enhancement of the working and defense capability, rehabilitation of individuals, i.e. an approach to solving the modern social problem of the growing ‘‘disability of society’’.

Modern medicine is highly dependent on recent developments in new diagnostic and therapeutic methods, techniques and equipment. An inventory of all existing medical equipment is essential to have a clear picture of the technology in use. INBIT undertook a project to create a regional-wide medical equipment inventory of all 85 medical centers belonging to the of the 2nd Regional Health Authority (RHA), most of them at Aegean Sea islands. Since the validity of the final project’s results mostly depends on data integrity and uniformity, two points are very critical: the methodology of registration and the use of correct codification and nomenclature. To this scope, parameters such as resources, inventory protocol, codification, and uniformity of the data, along with the adequate software tools to be used were designed and planned. Data to register included the manufacturer, model, serial number, medical device (MD) group, year of put in service, way of procurement, place that it is used/installed etc. A working team of nine biomedical engineers was formed with a specific and clear protocol on the procedure to be followed, with emphasis on the assignment of each device to the correct MD group. Additionally, given that equipment can be found anywhere in the medical centers, the cooperation of the healthcare staff was very crucial. Finally, since the inventory is dynamic, the establishment of update procedures has been designed and prepared and local staff was trained to keep up the inventory alive. The results were delivered to each healthcare unit and to the RHA authorities in an electronic form and uploaded to the web-Praxis medical equipment management system (MEMS), ready for implementation after user training.

The importance of medical devices in the delivery of high-quality medical services has grown considerably once there was a significant progress of the medical technologies. According to the international experience in the healthcare field, the success of the medical care services is largely due to the joint contribution of physician’s proficiency and the appropriate use of medicines and medical devices.Thus, medical devices are a key component of the medical practice, and subsequently, medical device safety and efficiency are a priority for the health system and the Government overall.

The association of alcohol use with in hospital trauma deaths remain unclear. This study tries to identify the association of blood alcohol content with outcomes.Methods: Four electronic databases (MEDLINE, research4life, PubMed, ScienceDirect) were searched from 2015 to 2021 using a search strategy. The search strategy included a combination of medical subject headings (Mesh), and variations of keywords such: trauma, polytrauma, injury, alcohol, ethanol positive, blood alcohol level, and outcome. Some studies concluded that there is a better outcome for BAC positive patients.Results: A total of 17 studies were published between 2015 and 2021. In total, were included 558577 trauma patients in 17 studies, number of patients ranging from hundreds to tens of thousands. Studies varied in the mechanism of traumatic injury, injury-related to specific body areas, patient ages. Also, studies vary about the level of BAC + (Blood Alcohol Content/concentration level). While other studies suggest an opposite opinion. It seems that data is more informative for TBI (Traumatic Brain Injury) where most studies related to a better outcome for trauma patients with BAC positive.Conclusion: Some studies present alcohol as a protective factor for trauma patients, while other studies present BAC as a worsening factor for patient outcome. No doubt that is necessary more studies in this direction.

The article reflects a clinical study on non-invasive monitoring of pulse rate and desaturation events with oximeter in chronic obstructive pulmonary disease (COPD) patients with cardiovascular comorbidities, in order to optimise the exacerbations diagnostic, predict the development of the complications and therapeutic approach. The presence of cardiovascular comorbidities in patients hospitalized with chronic obstructive pulmonary disease exacerbations is high and associated with rehospitalizations and deaths. Pulse oximetry is useful for non-invasive monitoring of hypoxemia presence and the severity of the patient's response to supplemental oxygen and other therapies, especially in emergency situations in exacerbated COPD and cardiovascular comorbidities.

Recently there have been a series of machine learning methods or deep learning architectures that have been developed and used in the field medical imaging. In this study, we focus on the use of AI in the field of breast imaging and the methods with the highest accuracy results for breast tumor segmentation and classification are presented, achieving robust results in detection. Extensive research which included more than 150 related published papers was performed, containing results published between 2016 to 2020 resulting in a review of 4 selected models all at the forefront of current progress.