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Supplemental Digital Content is available in the text., IMPORTANCE: Even with its proclivity for older age, coronavirus disease 2019 has been shown to affect all age groups. However, there remains a lack of research focused primarily on the young adult population. OBJECTIVES: To describe the epidemiology and outcomes of coronavirus disease 2019 and identify the risk factors associated with critical illness and mortality in hospitalized young adults. DESIGN, SETTINGS, AND PARTICIPANTS: A retrospective cohort study of the Society of Critical Care Medicine’s Viral Infection and Respiratory Illness Universal Study registry. Patients 18–40 years old, hospitalized from coronavirus disease 2019 from March 2020 to April 2021, were included in the analysis. MAIN OUTCOMES AND MEASURES: Critical illness was defined as a composite of mortality and 21 predefined interventions and complications. Multivariable logistic regression was used to assess associations with critical illness and mortality. RESULTS: Data from 4,005 patients (152 centers, 19 countries, 18.6% non-U.S. patients) were analyzed. The median age was 32 years (interquartile range, 27–37 yr); 51% were female, 29.4% Hispanic, and 42.9% had obesity. Most patients (63.2%) had comorbidities, the most common being hypertension (14.5%) and diabetes (13.7%). Hospital and ICU mortality were 3.2% (129/4,005) and 8.3% (109/1,313), respectively. Critical illness occurred in 25% (n = 996), and 34.3% (n = 1,376) were admitted to the ICU. Older age (p = 0.03), male sex (adjusted odds ratio, 1.83 [95% CI, 1.2–2.6]), and obesity (adjusted odds ratio, 1.6 [95% CI, 1.1–2.4]) were associated with hospital mortality. In addition to the above factors, the presence of any comorbidity was associated with critical illness from coronavirus disease 2019. Multiple sensitivity analyses, including analysis with U.S. patients only and patients admitted to high-volume sites, showed similar risk factors. CONCLUSIONS: Among hospitalized young adults, obese males with comorbidities are at higher risk of developing critical illness or dying from coronavirus disease 2019.

Хронічний перебіг пародонтиту та гінгівіту вражає до 80 % дорослого населення, стаючи одним із найпоширеніших серед хвороб людства. Захворювання ініціюється накопиченням бактерій вздовж ясенного краю і в просторі між ясенними тканинами та зубами. Відсутність клініки гострого болю при захворюваннях пародонта є однією з основних причин низького рівня звернень пацієнтів за стоматологічною допомогою. Діагностику захворювань пародонта, як правило, проводить лікар-стоматолог. Вона включає візуальний огляд тканин ясен та ряд інших протокольних процедур, у тому числі додоткових методів діагностики – клінічну оцінку рентенограми. Водночас, звичайні клінічні та рентгенографічні методи діагностики пародонта здатні лише до ретроспективного діагнозу, вони не можуть виявити або передбачити активність пародонтиту. Тому в останні роки активно досліджують потенційні біомаркери для діагностування хвороб тканин пародонта. Джерелом біомаркерів перш за все є ясенна рідина та слина, як такі, що безпосередньо контактують з ураженими тканинами. Враховуючи сказане, доцільно проаналізувати літературні дані щодо біомаркерів ясенної рідини та слини, які використовують для діагностики хвороб пародонта та можливості розробити прості у застосуванні тест-методи для ранньої діагностики. Мета дослідження – проаналізувати літературні дані щодо оцінки перспективи застосування біомаркерів у стоматологічній практиці, зокрема в діагностиці патології тканин парадонта разом із періімплантною патологією. Матеріали і методи. У дослідженні застосовано бібліосематичний та аналітичний методи. Результати досліджень та їх обговорення. У статті проаналізовано та опрацьовано джерела науково-медичної інформації, що стосуються застосування біомаркерів у діагностиці хвороб пародонта. Висновки. Незважаючи на те, що в діагностиці рогової рідини наявна значна кількість потенційних біомаркерів, проведені на сьогодні дослідження виявилися недостатніми щодо надання клінічно достовірної та корисної інформації для практиків з точки зору більш точної діагностики та планування лікування.

Background: International data on the epidemiology, ventilation practice, and outcomes in patients undergoing abdominal robotic-assisted surgery (RAS) are lacking. The aim of the study was to assess the incidence of postoperative pulmonary complications (PPCs), and to describe ventilator management after abdominal RAS. Methods: This was an international, multicentre, prospective study in 34 centres in nine countries. Patients ≥18 yr of age undergoing abdominal RAS were enrolled between April 2017 and March 2019. The Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score was used to stratify for higher risk of PPCs (≥26). The primary outcome was the incidence of PPCs. Secondary endpoints included the preoperative risk for PPCs and ventilator management. Results: Of 1167 subjects screened, 905 abdominal RAS patients were included. Overall, 590 (65.2%) patients were at increased risk for PPCs. Meanwhile, 172 (19%) patients sustained PPCs, which occurred more frequently in 132 (22.4%) patients at increased risk, compared with 40 (12.7%) patients at lower risk of PPCs (absolute risk difference: 12.2% [95% confidence intervals (CI), 6.8–17.6%]; P

The structural and electro-physical characteristics of ZnO/Si heterostructures deposited by the magnetron sputtering from aluminum-doped ZnO target are addressed. The film recrystallization and microcrystal structure restoration are observed. It is found that the ZnO/Si barrier is about 0.66 eV and depends on the annealing temperature of the implanted structures. Diode structures with a transparent electrode (ITO/ZnO/Si/Al) have photosensitivity in the wide spectral region of 0.4–2.5 µm. The photosensitivity mechanisms in different spectral bands require further refinement. The magnetron sputtering growth and the resulting film consolidation is interesting in which such varied morphologies have an impact on the photovoltaic behavior of ZnO/Si structures. Thus, the magnetron deposited ZnO layers with thicknesses of less than ≈70 nm has roughly 3 times greater photovoltage magnitude compared with that having greater thicknesses, and this coincides with the microstructural evolution of the film. The SPV decays slow down accordingly exhibiting decay times of the order 10 μs at the small film thicknesses and 100 μs at the ones exceeding ≈70 nm. These results can be interpreted in terms of the recombination and carrier trapping centers in the film and at the ZnO/Si boundary, whose concentration varies with the film thickness. In particular, increasing the grain size and grain density affects the composition and concentration of recombination-active defects at grain boundaries, which alter the carrier recombination rates. Carrier trapping at grain surface or interface states can dominate over fast carrier recombination processes, which also increases the photovoltage decay time. It is furthermore shown that forming p-NiO/n-ZnO/Si heterostructure increases the photovoltage magnitude, which is up to several times, and shortens the SPV decays. This can be effectively used in manufacturing rapid photosensitive elements.

Objective To investigate whether older adults with mild cognitive impairment (MCI) or dementia have higher rates of procedures requiring general anesthesia or intensive care unit (ICU) admissions compared with cognitively normal (CN) patients. Patients and Methods A population-based cohort, 70 to 89 years old at enrollment, underwent clinical and longitudinal neurocognitive testing to identify those with MCI and dementia. We analyzed the effects of cognitive status (CN, MCI, or dementia) at entry into the study from October 1, 2004, through December 31, 2014, on the risk of receiving procedures requiring surgical anesthesia and ICU admission. Results Of 2436 participants, 1977 (81%) were CN, 387 (16%) had MCI, and 72 (3%) had dementia. Cognitively impaired individuals were sicker. Compared with CN individuals, the likelihood of receiving a procedure requiring anesthesia was similar in participants with MCI (adjusted hazard ratio [aHR]=0.98; P=.78). Participants with dementia were less likely to receive these procedures (aHR=0.50; P=.02). Compared with CN participants, the likelihood of ICU admission for any indication was increased for those with MCI (aHR=1.24; P=.03) and dementia (aHR=1.59; P=.04). Admissions to the ICU after procedures were not different in patients with either MCI or dementia (aHR=0.96; P=.83 and aHR=1.01; P=.98, respectively). Conclusion Patients with MCI or dementia are not more likely to undergo surgery, and neither are they more likely to require ICU admission after procedures. An increased rate of nonsurgical ICU admissions requires vigilance to prevent deterioration of nonsurgical diseases that may lead to ICU admissions.

Transport theory for modeling the electric characteristics of high-quality p-n diodes has been developed. This theory takes into account a non-uniform profile of p- doping, finite thickness of the quasi-neutral regions and possible non-uniformity of the bulk recombination coefficient. The theory is based on related solutions of the Poisson equation, drift-diffusion equation and continuity equation with a generation-recombination term taking into account the simple band-to-band generation/recombination model. We have ascertained that the non-uniform profile of p-doping can lead to formation of p-n junctions with a specific two-slope form of the electrostatic barrier and two regions with the high built-in electric fields. We have found that at strong p + -doping the band structure of the InSb p-n junction has the form that can facilitate the emergence of additional mechanisms of current flow due to the tunneling and avalanche effects at the reverse bias. Using the literary data of the electron and hole lifetimes in InSb at cryogenic temperatures, we have found that the coefficient of bulk recombination can have an essential spatial dependence and considerably increases in the space charge region of p-n diode. The theory was applied to our analysis of p-n InSb diodes with p + -doping by using Be-ion implantation performed in ISP NASU. The theory predicts optimal conditions for detection of infrared emission. The technological process of fabrication, processing and testing has been described in details. Theoretically, it has been found that for parameters of the fabricated diodes and at 77 K the dark currents limited by diffusion and generation-recombination mechanisms should be less than 0.1 μA at the inverse bias of the order of 0.1 V. The measured diode’s I-V characteristics were expected to have strong asymmetry, however, dark currents are by one order larger than those predicted by theory. The latter can be associated with additional current mechanisms, namely: tunneling and avalanche effects.

The article analyzes the main aspects of the use of technologies of artificial intelligence in the political sphere. Technologies of artificial intelligence and «big» influence the main political processes of the leading countries of the world, building a world politics. Characterized by the main categories of artificial intelligence used in the political process. The process of using artificial intelligence technologies in the US presidential election in 2016, the presidential election in France and the referendum in the UK (Brexit) are considered. The main negative aspects of the application of methods and means of artificial intelligence in the political sphere and manipulation of public opinion are shown. The main perspectives of the use of technologies of artificial intelligence in politics and support of democracy in the world are determined. The main prospective models of use of means of artificial intelligence for improving the quality of work in the political sphere are outlined. The necessity of further researches on the use of artificial intelligence in the political process is substantiated.

Successful synthesis by vertical solidification (Bridgman - Stockbarger) technique is reported for a centimetre size noncentrosymmetric TlSbP2Se6 crystal (for the first time) with excellent transparency at 0.75–10 μm that is very useful for its practical application. The high homogeneity and stoichiometric composition have been confirmed by SEM-EDX. Next we determined the crystal structure, electronic properties by use of both experimental and theoretical methods. The layered structure of the crystal provides strong anisotropy of physical properties. Special attention was placed for an explanation of the source of the layer architecture and its effect on the strong anisotropy of properties. In particular, employing the XPS method, we have measured for the TlSbP2Se6 crystal the binding energies of core-level electrons as well as energy distribution of the valence electrons for both pristine and treated with Ar+ ions surfaces and shown that the TlSbP2Se6 crystal surface is highly hygroscopic. For interpretation and explanation of the measured XPS valence band spectrum, we examined different approaches for exchange correlation (XC) potential with a density functional theory (DFT) framework and found that the best agreement of the shapes of the XPS spectrum and the curve of total density of states is derived when the band structure calculations were made employing for XC potential modified Becke-Johnson (mBJ) functional in the form of Tran and Blaha. Based on the results of XPS measurements and calculations, we explained the contributions of individual ions to the band structure and convincingly demonstrated that ionic components of the chemical Sb–Se (P–Se) bonds in the TlSbP2Se6 crystal are similar to those of its silver-bearing counterpart AgSbP2Se6. The present DFT calculations within TB-mBJ + U + SO approach reveal that the TlSbP2Se6 compound is a non-direct semiconductor with Eg = 1.765 eV confirmed by UV-VIS measurements (1.75 eV). The main optical constants are explored in detail for TlSbP2Se6, as based on TB-mBJ + U + SO calculations. Finally, the result of the XPS investigations of the crystal surface after treatment with Ar+ ions supported by the calculations of the structure indicates its high chemical and mechanical resistance, which, despite the dangerous element contained in the composition, indicates its safe use in optoelectronic devices.

Supplemental Digital Content is available in the text., IMPORTANCE: At the start of the coronavirus disease 2019 pandemic, medications repurposed for management of coronavirus disease 2019 were used in the absence of clinical trial evidence. OBJECTIVES: To describe the variation and evolution in use of repurposed medications for coronavirus disease 2019. DESIGN, SETTING, AND PARTICIPANTS: Observational cohort study of adults hospitalized with coronavirus disease 2019 between February 15, 2020, and April 12, 2021, across 76 United States and international hospitals within the Society of Critical Care Medicine’s Discovery Viral Infection and Respiratory Illness Universal Study coronavirus disease 2019 registry. MAIN OUTCOMES AND MEASURES: Hospital variation was quantified using multivariable adjusted random effects logistic regression models and unsupervised clustering. Repurposed medications included antivirals, corticosteroids, hydroxychloroquine, immunomodulators, and therapeutic dose anticoagulants. RESULTS: Among 7,069 adults hospitalized with coronavirus disease 2019, 1,979 (28%) received antivirals, 2,876 (41%) received corticosteroids, 1,779 (25%) received hydroxychloroquine, 620 (9%) received immunomodulators, and 2,154 (31%) received therapeutic dose anticoagulants. Contribution of hospital site to risk-adjusted variation was 46% for antivirals, 30% for corticosteroids, 48% for hydroxychloroquine, 46% for immunomodulators, and 52% for therapeutic dose anticoagulants. Compared with the early pandemic, the later pandemic practice phenotypes converged with increased use of antivirals (odds ratio, 3.14; 95% CI, 2.40–4.10) and corticosteroids (odds ratio, 5.43; 95% CI, 4.23–6.97), with decreased use of hydroxychloroquine (odds ratio, 0.02; 95% CI, 0.01–0.04) and immunomodulators (odds ratio, 0.49; 95% CI, 0.34–0.70). There was no clinically significant change in the use of therapeutic dose anticoagulants (odds ratio, 1.01; 95% CI, 1.01–1.02). There were no differences in risk-adjusted mortality between hospitals with high rates of repurposed medication use compared with hospitals with low rates of use. CONCLUSIONS AND RELEVANCE: Hospital variation in the use of repurposed medications varied widely across hospitals early in the pandemic and later converged with the emergence of randomized clinical trials. Platforms developed for rapid activation and enrollment in clinical trials of repurposed medications are needed prior to the next pandemic to expedite effective, evidence-based practice.

Abstract Background: Pulmonary hypertension (PH) is a significant preoperative risk factor. We aimed to determine predictors of perioperative morbidity and mortality after noncardiac surgery for patients with precapillary PH. Methods: We conducted a retrospective cohort study of adults with pulmonary hypertension having surgery at a single large medical referral center. The PH and surgical databases were reviewed from 2010 to 2017. Patients were excluded if PH was attributable to left-sided heart disease or they had undergone cardiac or transplant operations. To assess whether PH-specific diagnostic or cardiopulmonary testing parameters were predictive of perioperative complications, analyses were performed using generalized estimating equations. Results: Of 196 patients with PH undergoing noncardiac operations, 53 (27%) experienced 1 or more complications, including 5 deaths (3%) within 30 days. After adjustment for age and PH type, there were more complications in those undergoing moderate-to-high vs low-risk procedures (odds ratio [OR], 4.17 [95% CI, 2.07 to 8.40]; P

IntroductionRobotic-assisted surgery (RAS) has emerged as an alternative minimally invasive surgical option. Despite its growing applicability, the frequent need for pneumoperitoneum and Trendelenburg position could significantly affect respiratory mechanics during RAS. AVATaR is an international multicenter observational study aiming to assess the incidence of postoperative pulmonary complications (PPC), to characterise current practices of mechanical ventilation (MV) and to evaluate a possible association between ventilatory parameters and PPC in patients undergoing RAS.Methods and analysisAVATaR is an observational study of surgical patients undergoing MV for general anaesthesia for RAS. The primary outcome is the incidence of PPC during the first five postoperative days. Secondary outcomes include practice of MV, effect of surgical positioning on MV, effect of MV on clinical outcome and intraoperative complications.Ethics and disseminationThis study was approved by the Institutional Review Board of the Hospital Israelita Albert Einstein. The study results will be published in peer-reviewed journals and disseminated at international conferences.Trial registration numberNCT02989415; Pre-results.

Dental examination of the population indicate that the prevalence of dentition in the children and adolescents (by criteria of dental aesthetic index – Dental Aesthetic Index (DAI, 1989) is the average 54 %. The aim of the study to research individual orthodontic indications in the pupils of junior school age in Uzhhorod. There were examined 152 junior pupils, – 46.7 % boys and 53.3 % girls. Materials and Methods. There was conducted dental examination, basic methods of which including: the height of the chin, breathing character, condition of the temporomandibular joint (TMJ), closing of the lips, nasolabial and chin folds, size of mouth slit, speech, harmful habits. The obtained data were recorded in a specially designed Table of orthodontic accounting indications. Results and Discussion. According to the research chin height was normal in 58.2 %, decreased in 33.5 % and increased in 8.2 %. More than a half of primary school children (55.3 %) had a breach of closing lips. Nasolabial and chin folds were expressed moderately in 58.6 % children. Among the most common bad habits were: bite lips and cheeks 84.8 % of the 152 investigated children. A substantial difference between the boys and the girls were found. Conclusions. We determined the following facts: studied orthodontic signs had a high prevalence among Uzhhorod children of primary school age. The specialists may strengthen the work with prevention of identified violations, involving parents, teachers, logopedists and dentists

In this work, following the crystallochemical analysis and electronic structural parameters of $$\hbox {Tl}_{4}\hbox {PbTe}_{3}, \hbox {Tl}_{4}\hbox {SnSe}_{3 }$$ and $$\hbox {Tl}_{4}\hbox {PbSe}_{3 }$$ single crystals, we predicted and experimentally demonstrated the second harmonic generation (SHG) and electrooptics effects for them. Photoinduced changes were performed by using the 7 ns UV nitrogen laser at wavelength 337 nm. The parameters of the SHG were determined through probing in to the reflected regime at wavelength of the 532 nm. The dependence of the output SHG versus photoinducing power density is studied. Explanation of the observed effect is given within a framework of the quantum chemical DFT simulations.

We have discovered substantial influence of the 3 μs CO2 laser treatment on the output third harmonic generation (THG) for Tl4SnS3 and Tl4PbTe3 single crystals. The treatment was performed in the regime of the pump-probing delay. The optimal pump-probe delaying time was 230 ps for the Tl4SnS3 crystals and 250 ps for the Tl4PbTe3 single crystals. It is crucial that for the Tl4PbTe3 the effect is substantially smaller. The effect may be explained within a framework of conception of excitation of the effective phonon subsystem effectively contributing to the THG.

Smart Learning Environments 3, 10 (2016). doi:10.1186/s40561-016-0035-1, Published by Springer Open, Berlin ; Heidelberg [u.a.]

The paper presents an approach for the cost effective implementation of simulationsupported training for plant operators. Simulation functions are seen as practical support for human cooperationwith complex automation systems. A web-based system architecture is proposed and a generic approach dedicated tomodeling and simulation of technical networks is applied. The concept has been developed within a project of the Fraunhofer Association e-Industrial Services. Aspects of system implementation and application are outlined.

Computer based models have become an indispensable means for the planning, optimisation and operation of industrial manufacturing systems. The usability and significance of the models strongly depends on their accuracy, availability and functional extent. Today, suitable models for components of automation systems are available only for some types of components. Functionality for simulation purposes is often limited and integration costs are often still considerable. These problems were widely solved for industrial robots in the 'Realistic Robot Simulation' (RRS) projects. There, world-wide standards for Virtual Robot Controllers (VRCs) were created. Now, this success should be transferred to other components of automation systems like programmable logic controllers (PLCs), human-machine interface (HMI) systems, bus systems and effector sensor systems.

Introduction: An uncommon association of chronic odontogenic osteomyelitis and an abscess in the right mandibular region with facial actinomycosis of 6 months duration after several short‐term therapy failures is described. Case presentation: The patient was a 55‐year‐old man with chronic inflammation of the right parotid area of the face. Actinomyces israelii, Fusobacterium nucleatum and Parvimonas micra were isolated from specimens of the subtemporal abscess. Therapy started as clarithromycin and was followed by amoxicillin/clavulanate because of the resistance patterns of co‐infecting F. nucleatum. Conclusion: In this case of facial actinomycosis, a successful therapeutic outcome involved a prolonged therapy as well as the detection of drug‐resistant co‐existing anaerobic bacteria.

THE PROBLEM OF DETERMINING the optimal financial structure is not confined to privately owned, value-maximising businesses in market economies but also exists for state-owned firms in regulated economies.1 Although extensive studies have been conducted on the general economic conditions in regulated economies (Kornai, 1980), the financial structure issues have largely been ignored. Research on the financial structure of value-maximising enterprises in market economies might be useful for state-owned firms (Myers, 1984), but the optimal financial structure for a company in a regulated economy may be different from that for an enterprise in an existing market-oriented economy owing to the different operating and financial environments (Granick, 1974). The transition from a centrally planned to a market economy might therefore entail significant innovative financial policy changes. In order to provide further insight into these issues, the financial structure of state-owned businesses in a regulated economy can be compared with those of privately owned businesses in a market-oriented economy. For this purpose, Hungary and West Germany are chosen. Hungary represents one of the first centrally planned communist countries to begin the path towards a market economy, while West Germany represents an example of a market-oriented economy that many reforming East European countries now wish to imitate (Der Tagesspiegel, 1990; and Nepszabadsag, 1990). In this article some testable characteristics of a regulated economy are briefly reviewed, the data and empirical findings are described, and the analysis is summarised.

An empirical analysis of the structure of Hungarian financial institutions reveals them to be very profitable across all groupings. Although capital and liquidity ratios are, on average, low in comparison to West German standards, the capital adequacy problems appear to be concentrated in the former affiliates of the central bank. The thinness and underdevelopment of the Hungarian securities market may hinder the capacity of the institutions to raise liquidity and capital ratios, as well as inhibit the emergence of competitors seeking high levels of profitability.

This paper focuses on the segmentation of 3D points from range camera data. Range cameras can capture 3D information of a scene by sending out infrared light and then measuring the reflections. A segmentation algorithm for the detection of planar surfaces is presented which is robust against erroneous data from the range cameras. It uses a grid of horizontal and vertical scanlines as intermediate primitives for the final planar region segmentation. By using the scanlines, the task of planar segmentation can be separated into two tasks which are less complex: line segmentation and line combination. The usage of higher primitives improves the segmentation time compared to the direct operation on the 3D point data. The algorithm is described in detail and evaluated on a test scene.

This paper focuses on errors which are possible to occur in the depth measurements of range cameras. Range cameras can capture 3D information of a scene by sending out infrared light and then measuring the reflections. Wrong measurements occur at the edges of objects where the depth level changes. A depth value between the foreground and background level is measured which creates a so-called "flying pixel" when displaying the 3D points.In this paper different methods for the identification of flying pixels are presented and compared. The advantages and drawbacks of each method are discussed. Then a simple method for the correction of flying pixel errors is presented and its limitations are shown. The final method for correction is presented which is based on segmenting the pixel matrix into horizontal and vertical scanlines. After segmentation, linear segments can be identified to which the pixels can be mapped. The paper concludes with the evaluation of the presented methods to show their effectiveness.

The aim of this study was to examine an in vitro dental plaque model for volumetric assessment and 3D reconstruction of experimentally bacterial induced caries-like lesions. Twenty-three extracted, impacted human molars were coated with a varnish leaving a 3 x 3 mm window on the smooth surface. The teeth were coated with human saliva and Streptococcus sobrinus 6715 adhered onto the enamel via a sucrose dependent mechanism. The coated teeth were incubated for 1, 7, 14 and 28 days. At the end of each incubation period microhardness was measured on three sectioned teeth of each incubation period at the enamel surface and at 450 and 750 microm depth perpendicular to the enamel surface. The enamel surface was investigated by scanning electron microscopy (SEM) prior to embedding and serial sectioning of 12 other teeth. The serial sections were studied with polarization light microscopy to investigate subsurface demineralization. The outlines of the caries-like lesions were then traced consecutively on transparencies, digitized and three-dimensionally reconstructed to demonstrate the expansion of the lesion into enamel for volumetric assessment. Microhardness was significantly reduced on the enamel surface after 7, 14 and 28 days incubation. The SEM investigation showed a surface demineralization with dissolution of the prism cores after 28 days incubation. Polarization light microscopy demonstrated caries-like lesions with an irregular expansion into enamel. The results demonstrate that the described method produces caries-like lesions which can be used for further experimental studies regarding demineralization and remineralization processes.

A new type of chalcogenide crystals Tl4SnS3, Tl4SnSe3, Tl4SnTe3 easily processing by external IR laser light is fabricated. For the titled crystals linear electrooptical effect was induced by external IR polarized light formed by two coherent beams of Er:glass nanosecond laser at fundamental wavelength 1540 nm. The detection of the electrooptical coefficient was performed by continuous-wave 1 W CO2 laser at probing wavelength 10.6 μm. The origin of the effect is caused by an occurrence of the thin (up to 50 nm) photoexcited nanosheets which forms near the surface space charge density non-centrosymmetry. The relaxation of the electrooptics after switching off of the photoinduced Er:glass laser beam is explored for different types of samples at different power densities. The crystals may be used for IR optical triggering.