The first case of coronavirus disease 2019 (COVID-19) in Brazil was diagnosed in February 2020. On March 20, the Ministry of Health issued Ordinance no. 467, regulating the use of telemedicine during the pandemic period. One of the various modalities of telemedicine is telemonitoring.To report our experience with telemonitoring and evaluate its applicability in the follow-up of the first 100 children who received the diagnosis of COVID-19 after visiting the emergency department of Sabará Hospital Infantil  and who had no indications for hospitalization.The care records of the children were retrospectively analyzed, and telephone contact with the families of patients who did not complete the proposed telemonitoring protocol was initiated.The average age of the children was 5.5 years, and a slight male predominance (54/100) was observed. Comorbidities were present in 24/100. The source of infection was family members living in the same household in 88/100 and other sources in 12/100. In the first telemonitoring, 44% of the evaluated patients were asymptomatic. In the second telemonitoring, 81% of the patients were asymptomatic. Telemonitoring was completed by 70% of the children. A total of 14 children returned to the emergency department, 11 of whom spontaneously (2/11 were admitted) and 3 under the indication of telemedicine (3/3 were admitted).Telemonitoring proved to be a clinically valuable resource in the follow-up of children with COVID-19, as it allowed continuity of care and identified patients with indications to return to the emergency department of Hospital Sabará and for hospitalization, thus avoiding unnecessary emergency department visits. As a result, numerous international borders were closed and social isolation became the recommended and adopted measure not only in Brazil but also worlwide.2The first case of coronavirus disease 2019 (COVID-19) in Brazil was diagnosed in February 2020.3 The COVID-19 pandemic stimulated significant changes in health care, such as accelerating the adoption of telemedicine.4In this context, on March 20, 2020, the Brazilian Ministry of Health issued Ordinance no. 467, regulating the use of telemedicine during the pandemic period.5According to Federal Medical Council of Brazil (CFM) Resolution no. 1643/2002, telemedicine is defined “as the exercise of medicine through the use of interactive audiovisual communication and data methodologies, with the objective of health care, education, and research”.6 For instance, studies have shown the potential of using mobile phones to help patients with diabetes in effectively managing their condition.7The incorporation of new technologies in the hospital environment has been increasingly realized in recent years, including the use of artificial intelligence, robots, and telemedicine itself. These new technologies have shown promising utility in the prevention and monitoring of diseases, and have especially contributed to increasing the level of treatment adherence among children and adolescents.8 In this context, telemonitoring, which is defined as the provision of medical guidance through the remote monitoring of a patient's health or disease parameters, is an important modality.9Remote patient care has been considered essential in the provision of health services worldwide during the COVID-19 pandemic.10 This medical service modality has a crucial role in minimizing physical contact between doctors and patients, thus contributing to breaking the chain of infection and optimizing health services.11Telemonitoring is an important tool that enables the continuity of health care provision, to the extent of identifying possible treatment complications, especially for patients who wish to maintain social distancing and avoid unnecessary visits to the hospital or clinic.Indeed, with the implementation of the telemedicine service in the emergency department of Sabará Hospital Infantil , telemonitoring of patients diagnosed with COVID-19 has proved to be relevant for the continuity of care at a time when social isolation is prioritized .This article aimed to report our experience with telemonitoring in the first 100 children diagnosed with COVID-19 in the emergency department of Hospital Sabará, and to describe the demographic and epidemiological characteristics of these patients. We also evaluated the usefulness of telemedicine in the follow-up of children with COVID-19 in relation to the detection of clinical worsening and the determination of the need for hospitalization or in-person re-evaluation.We hypothesized that the use of telemedicine can help in the fight against the COVID-19 pandemic.12Hospital Sabará is the second largest private and exclusively pediatric hospital in Brazil. Its emergency department receives an average of 100,000 children annually. It has 112 inpatient beds, distributed in inpatient units (70 beds) and intensive care units (42 beds).This was a retrospective observational study that analyzed the medical records of patients cared for in the emergency department of Hospital Sabará from April 17 to July 2, 2020, and were diagnosed with COVID-19. The data of the participating children and their family members were anonymized. Therefore, this experience report reveals no data of an identified or identifiable person and ensures the right of privacy of the analyzed patients, in accordance with the ethical principles of medicine. This study was approved by the research ethics committee of Fundação José Luiz Egydio Setubal (CAAE: 36495720.4.0000.5567).A total of 100 children were studied, and follow-up was performed using telemedicine. After a series of 100 cases, telephone contact was made with the families of the children who did not complete the telemonitoring protocol, to identify the causes of noncompletion and obtain data on the clinical outcome.®, which uses the Conexa network and the White Label platform (licensed software). After the appointment, a link to register on the platform was sent to the guardians. During the registration, free and informed consent terms were presented about the use of the technological platform for providing the service and about the personal data that will be processed by the hospital.To perform telemonitoring in the emergency department, we employed the telemedicine platform licensed to Hospital Sabará by Conexa SaúdeThis study included children aged from 0 to 17 years with a confirmed diagnosis of COVID-19, who were sent home after visiting the emergency department and signed the free and informed consent form for the use of telemedicine as medical care. Patients who needed the telemedicine service for other pathologies or those diagnosed with COVID-19 with indications for hospitalization were excluded from the analysis.All patients received initial in-person care following the institutional protocol. After the screening process, the pediatrician identified whether the child had, in the past 14 days, respiratory symptoms of probable infectious cause (with or without fever), such as cough, nasal congestion, runny nose, sore throat, dyspnea, or positive epidemiological history of exposure to a COVID-19 patient. If any of these symptoms were present, the patient was included in the group of suspicious children who subsequently underwent nasopharyngeal and oropharyngeal swabs for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for molecular detection using reverse transcription polymerase chain reaction (RT-PCR).Children suspected to have COVID-19 but had no indications for hospitalization were sent home after the collection of samples for RT-PCR for SARS-CoV-2. After the release of the RT-PCR test results by the laboratory, those with a positive result were included in the telemonitoring protocol, which was composed of two steps: (1) “first telemonitoring” performed within 48 h of discharge from the emergency department to inform the patients and their families about the positive result of the test for SARS-CoV-2 and to conduct the first clinical evaluation, and (2) “second telemonitoring” performed 7 days after the first telemonitoring to re-evaluate the patients' clinical condition .In both steps, the guardians were asked about the evolution of respiratory symptoms; the presence of fever, vomiting, diarrhea, diuresis, and skin spots; and the food acceptance of the children. The two steps of telemonitoring were performed to follow up the evolution of COVID-19 in the patients, to proactively identify the possible need to return to the emergency department and for hospitalization.Between April 17 and July 2, 2020, 1237 patients cared for in the emergency department of Hospital Sabará had a diagnostic suspicion of COVID-19. Among all patients with clinical suspicion (age 0–17 years), 124 (10%) had a diagnosis of COVID-19 confirmed by a nasopharyngeal or oropharyngeal swab test for SARS-CoV-2 by RT-PCR. Of these 124 children, 24 were admitted after face-to-face evaluation in the emergency room (12 in an inpatient unit and 12 in an intensive care unit).The remaining 100 patients who had no indications for hospitalization after the first visit to the emergency department of Hospital Sabará constituted the group of eligible children and were included in the telemonitoring group (“study group”). The average age of the children in the study group was 5.5 years, and a slight male predominance (54/100) was observed. The presence of comorbidities was verified in 24 of the 100 children, among which neurological conditions, asthma, and trisomy 21 were the most common. With respect to the infection source, family members living in the same household were determined to be the source in most of the cases (88/100). A different source was identified in only 12 of the 100 children.13 , and the second telemonitoring in 70 patients (70%). The causes of failure in telemonitoring were difficulties in contacting the patients for scheduling purposes (18), unavailability of time of the families (5), insecurity of family members in performing the care of their children with remote guidance (3), internet connectivity issues (2), and decision of some families to continue the care of their children using other health services (2).After the second telemonitoring, telephone contact was made with 30 families whose children did not fully adhere to the protocol. The contact was made by only one physician who performed structured interviews to evaluate clinical evolution, possible admissions to other institutions, and reasons for nonadherence to the proposed telemonitoring protocol. A maximum of three attempts were made to contact each family. The contact was successful in 28 cases. Successful contact was made in all eight families that did not comply with the protocol of the first telemonitoring. Among the 22 families that did not comply with the protocol of the second telemonitoring, 20 were successfully contacted. Thus, considering the 70 cases that fully adhered to the telemonitoring protocol and the 28 cases with successful telephone interviews, our follow-up rate in this series was 98%.n = 92) of the evaluated patients were already asymptomatic. In the second telemonitoring, performed in the subsequent 7 days, the percentage of asymptomatic patients was 81% (n = 70). That is, in most of the evaluated cases, there was no persistence of symptoms 9 days after the first visit to the emergency department of Hospital Sabará, as shown in In the first telemonitoring, performed within 48 h of discharge from the emergency department, 44% , persistent fever (n = 3), headache (n = 2), irritability (n = 1), lack of appetite (n = 1), need for guidance (n = 10), epistaxis (n = 1), colic (n = 1), and presence of rash (n = 1).The average age of the children who returned was 4.5 years. Of these, three children had comorbidities. The reasons for the return were tiredness . In 11 cases, the families spontaneously decided to return to an emergency service without an indication under the telemonitoring protocol. Of them, 10 returned to the emergency department of Hospital Sabará and 1 sought emergency service from another hospital. Of these 11 cases, 2 had indications for hospitalization .p = 0.0495), which suggests the clinical utility of telemedicine in reducing unnecessary visits to the emergency department, as shown in Telemedicine indicated the need to return to the emergency department, as a tool that determines the risk of hospitalization. Although the low number of cases leads to a large uncertainty of the odds ratio , the OR achieved statistical significance (n = 24) was 5 days and that of patients hospitalized after telemonitoring was 4 days. Although 24 (24%) children in the study group (n = 100) presented at least one comorbidity, only 1 child in this group needed to be hospitalized, as shown in The average length of stay of the patients hospitalized after the first care in the emergency department  maintenance of social isolation, by reducing unnecessary visits to hospitals or clinics; (2) reduction of the time in the emergency department, enabling less exposure to and contact with other patients; and (3) increased safety, involving remote postdischarge follow-up by the emergency department with the possibility of early detection of clinical deterioration.The most relevant difficulties associated with telemonitoring were related to the technological aspect of the service, such as possible connection failures, contact difficulties, or scheduling with families. Moreover, the relative insecurity of patients and their families about this type of remote health care provision presented a challenge in the development of the patient–emergency doctor relationship.15Among children who returned to an emergency service for a new in-person evaluation, all patients who returned under the indication of telemedicine were hospitalized, whereas only 2 of the 11 children who spontaneously returned were eventually judged to have an indication for hospitalization. This shows the clinical utility of telemonitoring in reducing unnecessary visits to emergency departments.The average length of hospitalization in the children who were subsequently admitted was shorter than that of the children admitted after the first in-person evaluation, which indicates that telemonitoring is safe and can detect the appropriate time of re-evaluation, without resulting in worsening of the patients' condition. Among the children with comorbidities, only one needed hospitalization, which proves that telemonitoring is also useful and applicable for children with previous diseases or comorbidities.16 and information about COVID-19 in children was still rare and uncertain.One of the strengths of this study is that telemedicine was investigated in an exclusively pediatric hospital in the city of São Paulo, Brazil, at a time when the number of COVID-19 cases was rapidly increasingHowever, the small number of patients in this study compromises the accuracy of the presented information. In addition, it is important to recognize that the study was conducted in a pediatric population from a private hospital in a large urban center in Brazil. In reality, access to telemedicine is still limited for the low-income population, owing to the lack of equity in internet access and the limited coverage by health operators for this new service. These issues still pose a challenge to the mass dissemination of telemedicine and to obtaining greater knowledge about the use of such technology.15The findings of this study corroborate the conclusion of other studies that sought to investigate the use of the technology in the health field: telemedicine is a useful resource in the care of patients with COVID-19.Further studies with a larger number of patients are needed to confirm our research data and to further prove the effectiveness of telemonitoring. New studies may also focus on the incorporation of telemedicine in hospital departments other than the emergency department and on the applicability of telemedicine in the monitoring of diseases other than COVID-19.In conclusion, telemonitoring proved to be a useful resource for the continuity of care and identification of cases requiring hospitalization after visiting the emergency department of Hospital Sabará. Telemedicine is an effective and safe alternative for monitoring children diagnosed with COVID-19.


Using that method, the obtained results are presented in images only; thus, for the extraction of quantitative values of phase velocities, additional algorithms should be used. In this work, the 2D-FFT method is presented, which is based on peak detection of the spectrum magnitude at particular frequencies for obtaining the quantitative expressions. The radiofrequency signals of ULWs (ultrasonic Lamb waves) were used for the accuracy evaluation of the method. An uncertainty evaluation was conducted to guarantee the metrological traceability of measurement results and ensure that they are accurate and reliable. Mathematical and experimental verifications were conducted by using signals of Lamb waves propagating in the aluminum plate. The obtained mean relative error of 0.12% for the A0 mode (160 kHz) and 0.05% for the S0 mode (700 kHz) during the mathematical verification indicated that the proposed method is particularly suitable for evaluating the phase-velocity dispersion in clearly expressed dispersion zones. The uncertainty analysis showed that the plate thickness, the mathematical modeling, and the step of the scanner have a significant impact on the estimated uncertainty of the phase velocity for the A0 mode. Those components of uncertainty prevail and make about ~92% of the total standard uncertainty in a clearly expressed dispersion range. The S0 mode analysis in the non-dispersion zone indicates that the repeatability of velocity variations, fluctuations of the frequency of Lamb waves, and the scanning step of the scanner influence significantly the combined uncertainty and represent 98% of the total uncertainty.The 2D-FFT is described as a traditional method for signal processing and analysis. Due to the possibility to determine the time and frequency ( As a result, the image  of the measured array signals is projected [t,f) domain can be determined. It is the primary condition to analyze the non-stationary/multimode signals, such as ultrasonic Lamb waves (ULWs).In 1991, Alleyne and Cawley were the first . Using trojected ,4. By apt,f) domains and allow displaying them [n) and antisymmetric (An) modes, which emerge depending on the thickness of the object, the material under investigation, and the frequency; and every one of them is described by two velocities, namely phase and group [f,k) energy trajectories, is considered to be a good tool for the analysis of such a signal. However, there is one significant drawback to this method. The obtained results are presented in images, and additional algorithms have to be used for the quantitative expressions. As a result, a number of various signal-processing algorithms are created and used for the quantitative display of  domains for the dispersion evaluation of Lamb waves [f,v) are constantly developed and researched. However, it should be noted that, in order to estimate the location and size of the defect based on phase-velocity changes, at first it is necessary to know the reliability of these methods. Therefore, an assessment of the accuracy of any method developed must be performed.Ultrasonic inspection is becoming a standard method in Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM) applications . As a reing them ,8,9. Anond group . Therefomb waves ,11. Thenmb waves  and provmb waves . As presmb waves , not onlIn the presented work, the focus is on the reliability evaluation of the 2D-FFT method that is based on peak detection spectrum magnitude at particular frequencies. This signal-processing method was developed and presented in our previous work . The inv(1)Development of an algorithm of the signal-processing method.(2)Mathematical modeling of the dispersion curve segments. The purpose is to identify the capabilities of the most accurate reconstructed segments and determine the uncertainty components associated with the model errors.(3)Experimental setup and verification of the results.(4)0 and S0 modes.Determination of input and output parameters, which affect the final method accuracy. Optimization of the selected uncertainty components for uncertainty quantification in high-dispersion and non-dispersion zones of phase-velocity dispersion curves of the AValidation of the signal-processing method is an important and necessary part, as it helps to avoid costly and time-consuming practices and ensure the comprehension of the method efficiency . All invThe main task of the presented work was to evaluate the accuracy of the 2D-FFT method based on the peak detection of the spectrum magnitude at certain frequencies, using the signals of Lamb waves propagating in a homogeneous aluminum plate. Using the general principles of measurement theory, we identify, analyze, and present the main characteristics and sources of uncertainties that mainly affect the accuracy of the obtained results. It benefits laboratories that evaluate the uncertainty of their measurement results when demonstrating their technical competence upon their certification/audit in accordance with SO/IEC 17025:2017.The paper is organized as follows: The technique of peak detection of the spectrum magnitude from the 2D-FFT image is introduced in As mentioned in the introduction, using the 2D-FFT method, the distance and time are transformed into the wavenumber and frequency space, and an image of a 2D data array is obtained. To obtain quantitative expressions, the technique of peak detection of 2D spectrum magnitude is proposed, which was presented in the previous work . TherefoI.0 mode phase-velocity curve obtained by this method is displayed in Application of the 2D-FFT method for analysis of the B-scan data. Since the 2D-FFT method is well-known, the mathematical equations are not given, but the segment of the AII.f1 up to f2).Selecting the frequency bandwidth (from Estimating the phase velocity of Lamb wave modes from the 2D-FFT image and applying the peak detection of 2D spectrum magnitude at maximum energy and particular frequencies (within the selected frequency bandwidth).The second-order polynomial approximation is applied in order to reduce the influence of scattering effects of detected peaks of phase velocity due to the presence of blurred shapes of 2D spectrum magnitude.Detection of 2D spectrum magnitude peaks includes the following steps:The algorithm consists of two main stages: the 2D-FFT method application and calculation of peak detection of 2D spectrum magnitude of the acquired signals:ρ = 2780 kg/m3; Young’s modulus, E = 71.78 GPa; and Poisson’s ratio, ν = 0.3435.Based on the methodology for the reliability evaluation of the signal-processing methods used for the dispersion estimation of Lamb waves presented by Draudviliene and Meskuotiene , the matThe next step of the presented study is a selection of the frequency range. For that purpose, the phase-velocity dispersion curves of the asymmetric and symmetric modes of Lamb waves are required. The analytical computational package ‘DISPERSE’ was chosen , and usi0 mode is highly dispersive; meanwhile, the S0 mode shows a weak dispersion level. Thus, the three-period harmonic bursts with Gaussian envelop that have a frequency of 160 kHz are used as the input signal, IFT denotes the inverse Fourier transform; x is the propagation distance, ω is the angular frequency; and j is the basic imaginary unit, Based on the obtained phase-velocity dispersion curves, the frequency range up to 300 kHz and possessing a central frequency of 160 kHz is selected for the study, where the Aollowing :(1)ux(t)x step of 0.1 mm is used to obtain the signals of both A0 and S0 modes. In this way, 2001 simulated signals for both modes are obtained, which are displayed in two B-scan images. The images of B-scans of the A0 and S0 modes are presented in A 200 mm distance with a dHaving the simulated signals, the 2D-FFT method and technique of peak detection spectrum magnitude can then be applied. Likewise, the technique reliability evaluation at the theoretical level can be obtained.0-mode phase-velocity dispersion curve segment at the 160 kHz frequency range was reconstructed, and the image is presented in 0 mode in numerical values were retrieved. The reconstructed A0-mode phase-velocity segment, which was created by calculating the peak values of spectrum magnitude at particular frequencies, is presented in Using the 2D-FFT method, the AAccording to Reference , the finn = 1, …, N, nth point of the dispersion curve, N is the number of points in a segment of the dispersion curves, The absolute error and the average of absolute errors are calculated as follows:The standard deviation represents the reliability of the method at the theoretical level, and it will be included in the uncertainty budget. The obtained results are presented in 0-mode phase-velocity dispersion and reconstruction dispersion curve segment in a clearly expressed dispersion zone. The repeatability of the variation of the measured points of dispersion curves is a part of the combined standard uncertainty and is equal to 0.2%. The relative standard deviation was calculated as follows: The phase-velocity dispersion curve was reconstructed in the frequency domain covering 160 kHz, with an average relative error of 0.12%. Based on the result, one can assume that the proposed method is a reliable tool for the evaluation of the A0 mode. The retrieved results are presented in The same procedure was applied for analyzing the suitability of the proposed technique of the peak detection spectrum magnitude for evaluating the phase-velocity dispersion by reconstructing the dispersion curve of S0 mode, which is analyzed in the very high dispersion zone, the different frequency components propagate at different velocities and are distributed in a wide frequency range, which covers  showed that variations of the phase-velocity components are covering a very narrow range of distribution. Thus, the second-order polynomial approximation of more densely concentrated phase-velocity values in terms of frequency generates some errors. The obtained discrepancy of values is presented in The comparison of the obtained results c shows t 180 kHz a, the de 180 kHz c; thus, 0 mode possesses a high dispersion nature is selected.Thus, in order to summarize the efficiency of the proposed method for using the dispersion evaluation of Lamb waves, an additional study needs to be conducted. In relation to that, the frequency range where the S0 mode at the central frequency of 700 kHz (frequency range from 400 kHz up to 1000 kHz) possesses a very high dispersion nature. Thus, the three-period harmonic bursts with the Gaussian envelope and having a frequency of 700 kHz are used for simulating the input signal 0 mode –(4), we performed the calculations of the mean absolute, relative errors, and standard deviation, and these are presented in 0 mode  of 2 mm in thickness was chosen for the experimental research of the Lamb-wave propagation properties. The parameters of the aluminum alloy plate used in the experiments were the same as those in the mathematical verification and described in An isotropic aluminum plate . A detailed description of the transducers is provided in Reference . The two0 and S0 modes from using the 2D-FFT method and the numerical estimations of phase-velocity values from using the technique of peak detection of spectrum magnitude were obtained and are presented in 0 and S0). The results obtained in each case were compared by using the same reference method.The same procedure as in the mathematical investigation is used to analyze the reliability of the method for the experimentally obtained signals. The images of the phase-velocity dispersion curve segments of the A0 mode is analyzed in the non-dispersive range; therefore, the detected peak values coincide, and the dispersion curve is reconstructed in a narrower frequency range.As mentioned above, the Sk = 1,…; K is the kth point of the segment; K is the number of points in a segment of the dispersion curves; In order to evaluate the quantitative characteristics of the method accuracy, a systematic error of the experimental values from conventional true values should be estimated ,21. The The scatter of values obtained from repeated measurements is characterized by the standard deviation of phase velocity, which is calculated as follows:0 and S0 modes and the standard deviation are presented in The mean absolute and relative errors for the A0 mode was obtained. As values of the reconstructed dispersion curve from the experimental signals at the corresponding points for the S0 mode were lower than the corresponding values of the reference dispersion curve  and the ultrasonic signal frequency, f. Likewise, the approximate Δi)F kHz is (1590 m/s + 0.6%) ± 2.6%. The result of the velocity measurement for the S0 mode in the range (137.5–186.5) kHz is (5402 m/s − 1.6%) ± 1.6%. These results are presented in the following form: . The GUM uncertainty framework is based on the law of propagation of uncertainties (LPUs) . The comAs observed in 0 mode was studied in the non-dispersive zone; meanwhile the A0 was in the clearly expressed dispersion zone [0 mode more accurately, only with a 0.6% mean relative error. Meanwhile, the phase velocity of the S0 mode was reconstructed with a 0.65% mean systematic error, using the zero-crossing technique. Moreover, it is 2.5 times more accurate than in the case of the 2D-FFT method. The assessment of the reliability of developed methods indicates that the 2D-FFT method is more suitable to be used in the studies, which provide an evaluation of the clearly express dispersive zones. Thus, assessing the reliability of developed methods is a necessary task that can be used to assess the accuracy of developed methods compared to other methods and to make it easier to choose the most appropriate method needed to solve the specific problem or task.We performed a comparison between the obtained results for our method and the results obtained by using other phase velocity evaluation methods. Using the zero-crossing technique, we determined that the excitation frequency for both modes was 300 kHz, which means that the Sion zone . Thus, t0 mode at 160 kHz and 0.05% for the S0 mode at 700 kHz in the mathematical investigation indicate that the proposed method is particularly suitable for evaluating the phase-velocity dispersion by reconstructing dispersion curves in clearly expressed dispersion zones. The uncertainty analysis has shown the components that significantly affect the measurement result under different conditions. The plate thickness, mathematical modeling, and scanning step of the mechanical scanner have a significant impact on the estimated uncertainty of the phase velocity for the A0 mode. Those components dominate and make about ~92% of the total standard uncertainty. The combined uncertainty in the non-dispersive zone for the S0 mode is sensitive to the repeatability of velocity variations, fluctuations of the Lamb wave’s frequency, and the scanning step of the scanner. These three components represent 98% of the total uncertainty. The obtained results for the phase-velocity measurement for the A0 mode in the range (114.3–213.6) kHz and the S0 mode in the range (137.5–186.5) indicate that the proposed method is a reliable tool for the quantitative evaluation of the phase velocity using Lamb waves. This will facilitate the selection of the method according to the required parameters, solving one or another problem in various future studies.An implementation of the 2D-FFT method based on the technique of peak detection of the spectrum magnitude at particular frequencies was presented. Mathematical and experimental verifications using signals of Lamb waves propagating in the aluminum plate were performed. A major focus was given to the experimental results obtained for the systematic error, which plays a significant role in the overall error contribution and expanded uncertainty, which characterizes the quality of measurement results. The obtained mean systematic error of 0.6% for the A


Vertebrobasilar insufficiency (VBI) is one of the most common forms of cerebrovascular pathology. The progression of the VBI, especially in the context of inadequate therapy, often leads to the formation of a persistent neurological deficits within the framework of dyscirculatory encephalopathy and the consequences of a stroke in the vertebrobasilar system. This study demonstrate the importance of objective methods of patient investigation to optimize the choice of the most effective methods of surgical treatment for VBI in cases of ineffective medical treatment. We have shown that the optimization of the diagnostic algorithm contributes to the correct individualized determination of types of surgical treatment for patients with VBI. It was found that, in addition to traditional diagnostic methods, the use of radiographic methods  is invaluable for choosing the tactics of surgical treatment. We propose a significant outcome indicator like the blood flow reactivity index to determine the postoperative improvement of blood flow in the vertebral arteries. In addition, the need to perform cerebral angiography and consultations with related specialists to exclude pathologies with a similar clinical picture is emphasized. Ischemic disorders in the vertebrobasilar system occur in 30% of all cerebrovascular diseases and 70% of cases presenting with clinical features of transient ischemic attacks. Mortality from ischemic strokes in the vertebrobasilar system is twice as high as the death rate from strokes in the carotid system –6. There. These factors make it much more difficult to identify clinical and neurological signs of vascular pathology and predetermine the use of topical diagnostics to guide treatment  and its stenosis are established, associated with age-related changes and stenosis of other major blood vesselsreatment , 8. Howereatment , 5, 6, 9Figure 1.The Study design is a single-center retrospective-prospective cohort-controlled clinical trial involving 100 patients who were treated at the 3rd Central Military Clinical Hospital named after A.A Vishnevsky  from 2009 to 2019. In all 100 VBI patients were confirmed and various significant stenotic-occlusive lesions of the V1 segment of the VAs were identified. The presence of pathological tortuosity of the VAs was also recorded. This study was approved by the 3rd Central Military Clinical Hospital named after A.A Vishnevskyand implemented in accordance with the principles of the Helsinki Declaration . Written informed consent was obtained from all subjects. The general patient distribution by clinical diagnosis was analyzed as indicated in Figure 1 above, it indicates the reliability of the clinical diagnosis based on the associated clinical picture. Since the data are obtained in percentage form, it is important to note that the clinical signs of one patient could have several of these characteristics. Thus, the chances of making an error in the clinical diagnosis were eliminated. In addition, the sex-age factor was excluded, since the distribution of 100 patients by sex and age formed a comprehensive picture of the examination and the reliability of the results obtained based on the data of the sample characteristics. The average age of the patients was 72.2 years and the risk of the disease was highest between the ages of 45 and 89. In this study, 58% were men, and 42%, were women. In 50% of patients, diffuse encephalopathy syndrome (DES) was present in the vertebrobasilar system (VBS) , 7% had a history of transient ischemic attack (TIA) in VBS, and 4% had a history of VBI in VBS. Comorbidities were present in 98% of patients. These are presented in Table 1.As shown in n = 50) and sonservative treatment group (n = 50).Depending on the leading lesion of any arterial segment involved in the blood supply to VBS in the presence of stenotic-occlusive lesions of the V1 segment of the VA, all 100 patients were divided into 2 groups: the surgical treatment group .A.• Assessment of radial artery pulses or the establishment of the presence of auscultative VA murmur in the neck or supraclavicular region;• Presence of blood pressure asymmetry on the hands of more than 20 mmHg.General clinical examination:B.• Compression diagnostics tests .Clinico-neurological examination (by a competent neurosurgeon):Stage 2: identifying the level of obstruction in the suspected vessels. - doppler u/s of the brachiocephalic artery: analysis of the diameter of arteries, velocity and volume analysis of the blood flow; - loading tests to determine perfusion reserve (turning and tilting of the head); - Analysis and calculation of the reactivity index of VA; - calculation of the total blood volume; - Transcranial doppler.Stage 3: use of radiologic diagnostic methods: - Brain computerized tomography (CT)/magnetic resonance imaging (MRI): morphology of subtentorial and supratentorial structures of the brain; - CT or MRI-angiography: main arteries of the brain, anatomy of the posterior cerebral artery (PCA), excluding trifurcation of carotid arteries); - cerebral angiography of each segment of the VA, patency, morphological and functional status of the posterior circulation including compression tests.As a result of the analysis of neurological disorders, statistical indicators were determined for surgical treatment in the presence of the entire clinical complex of discoordination, vestibular-ataxia syndrome, auditory and visual disorders. Based on the proposed diagnostic algorithm, it is possible to predict the type of surgical treatment using the above indicators.1.Predominant clinical features of VBI,2.No significant defects of the VA and subclavian artery,3.Carotid stenosis more than 70%,4.Lack of decompensation in the vertebrobasilar system.The data for the clinical features of the patients in 1st group was as tabulated below (A).The inclusion criteria for the anastomosis included:n = 6): Dyscirculatory encephalopathy in VBI , TIA in VBI  and acute cerebrovascular accident in VBI .Of the 6 patients, vertebral circulation was closed (group 1.A) in 4 (66.7%) and open in 2 (33.3%) (group 1.B). Preoperative clinical manifestations of VBI in group 1 patients .Features of diffuse encephalopathy in the VB system were seen in 15 (42.9%) patients, TIA in 7 (20%) patients, 13 (37.15%) presented with acute vascular compromise in the VBS. Abnormalities of coordination, auditory and visual systems were the most common preoperatively. However, postoperatively, auditory symptoms persisted in most patients  patients with occlusion of the V1 segment of VA,- IIB - 15 (24.3%) patients with local, limited subtotal stenosis of the V1 segment of the VA (greater than 70%).Both groups had reconstruction of the V1 segment of the VA. The division of patients by type of performed operations is presented in The inclusion criteria for this group included:These patients underwent Arteriolysis, X-ray endovascular stenting, and Arterioplasty.1.chronic ischemia in the distribution of the VB system;2.VA atherosclerosis in the V1 segment of the VA;3.Bony compression of VA in 2 segments was excluded;4.Transient ischemic attacks;5.Stroke in the VB system.The preoperative and postoperative clinical features in these patients are tabulated in C.The inclusion criteria in this group included:One of the main factors for the neurosurgeon to consider when choosing the operative technique is the analysis of the V1 segment variability , 12, whi1.See criteria for group 3;2.coiled V1 segment of the VA;3.High mortality risk.Assessment of clinical features of patients in group 4 is shown in D.The inclusion criteria included:In this group, surgery on the V1 segment of the VA was performed as follows: 2 parients underwent angioplasty, stenting of the right vertebral artery (RVA), 1 patient underwent left scalenotomy, and 1 patient underwent eversion carotid endarterectomy on the left with resection of the pathological loop and redressing of the left vertebral artery (LVA).Supplementary Figure 7).In practice, we propose using the presented diagnostic algorithm, with the mandatory inclusion of the following elements: (1) to emphasize the need to exclude diseases with a similar clinical picture; (2) CT-angiography of the 4 segments of the VA and the basilar artery (BA); (3) analysis of the curvature of the vertebral circulation; (4) establishing the type of collateral compensation; (5) and the use of a significant outcome indicator like the blood flow reactivity index (n = 50) was included to function as controls for comparison with the surgical treatment group (Table 2). Following the use of the above algorithm, the selected types of operations produced improvement in blood flow through the VAs in equal measure (Table 3).The conservative treatment group which was receiving medical treatment (p < 0.05). An increase in the total volumetric blood flow of more than 250 mL/min was observed in most patients after various types of operations on the 1st segment of the VA.When analyzing the volumetric blood flow rates, it was noted that among the operated patients, a decrease in the clinical features of VBI was observed in patients with an increase in the total volumetric velocity of blood flow in the VA of more than 250 mL/min (Favorable outcomes including a decrease or disappearance of the clinical features of VBI were observed in most patients with an increase in total volumetric blood flow through the VA to 250 mL/min or more, and unfavorable outcomes i.e. deterioration or return of the clinical features of VBI was seen in patients with post-surgical total volume blood flow in the VA of less than 250 mL/min and all patients of the control group.The use of the diagnostic algorithm contributes to the accurate prediction of the type of surgical intervention for various patients with vertebrobasilar insufficiency. In addition to traditional diagnostic methods, the gold standard investigations to guide the surgical intervention are radiological investigations including ultrasonic Doppler, contrast-enhanced multispiral CT, and CT-angiography. The need to perform cerebral angiography and multidisciplinary specialist consultations to exclude pathologies with a similar clinical picture cannot be overemphasized.


The developed method worked with a rectangular counter electrode without a guard ring assist, during an individual impedance measurement. The impact of the counter electrode size on the impedance spectra was verified in the first stage by tests conducted with ten types of counter electrodes. The obtained results in the form of empirical spectra were represented by theoretical spectra using the 3D model and the matching degrees were within a range of 0.96–1.73 at the expected level of 1.00. The obtained results in the form of spectra distribution were accurately represented by simulations with the 3D model. In the second stage, the iterative procedure for determining the polarization area of reinforcement in concrete was positively verified for additional test elements. Electrochemical parameters of the steel-concrete system were determined on the basis of the 3D model with a simultaneous adjustment of the polarization area on the rebar. In this case, the expected matching degree of 1.00 was obtained for each tested system after more than ten iterations starting from matching the model spectra to the empirical spectra at the level of 0.31–0.93.A new method is proposed for determining the test surface of steel rebar in concrete during polarization measurements of corrosion rate of reinforcement using the method of Electrochemical Impedance Spectroscopy. The methodology was based on the original  The operational safety of large concrete structures can be provided by their administrators, who should have detailed knowledge of their technical conditions . FacilitThe most popular method consists of the application of twin counter electrodes placed in one head on the surface of the concrete cover over reinforcement. The auxiliary electrode is described as a guard ring that is used to confine distribution of polarization currents on the side surface of cylindrical reinforcement. The idea of guard ring has been repeatedly described and experimentally verified ,45,46,47The second method of identifying the polarization surface of reinforcement, which is also described in the available literature, is to perform a series of measurements, each time using a counter electrode of a different size. Finally, the distribution of outcomes of polarization resistance against the counter electrode surface can be analysed by extrapolating true values of polarization resistance for the projected unlimited polarization surface of the test electrode. The above testing method was described in the paper  as a conThe third, a laboratory and in situ verified method of identifying the polarization surface of reinforcement, is based on cutting a cylindrical core with part of the support rebar from the reinforced concrete structure. Then, a three-electrode system composed of an auxiliary electrode, a reference electrode, and a working electrode, which is a part of the cut rebar from the core, is arranged on the cylindrical core under laboratory conditions. Because geometry of the cut rebar is known, its side surface is also defined. Additionally, this side surface can be verified after crushing the core in the testing machine. Key information for testing the polarization surface of reinforcement is automatically acquired during the EIS measurements on such a core. Additionally, a possibility for simulating variable thermal and humidity conditions in the environment of the structure in a climatic and corrosion chamber provides a range of extreme values of the corrosion ratio instead of a single value obtained from traditional measurements. The above methodology for polarization tests on concrete cores was patented in 2012 and is also presented in the papers ,49,50,51Another, fourth, method of identifying the polarization surface of reinforcement covered with concrete is to make a cylindrical cut in the concrete cover to a depth corresponding to its thickness prior to the EIS measurements. This circular cut should have a diameter equivalent to a cross-sectional diameter of the counter electrode, which is placed on the concrete surface through wet felt. The cut, which is recommended to be filled with liquid insulator, ensures relatively effective confinement of distribution of polarization currents over the side surface of steel reinforcement. The test surface of reinforcement can be estimated because the effects of the insulator are known. This methodology was patented in 2020, and its experimental verification is discussed in the papers ,52,533D model of the steel-concrete system. The model, which is a base of the proposed methodology, has already been described and partially verified during tests concerning the impact of diameters [3D model.In the search for non-destructive methods for identifying the polarization surface of reinforcing steel in concrete, this paper suggests a new methodology that requires only one EIS measurement with a single counter electrode and the analysis of results is enhanced with an original iameters  and the iameters , the thiiameters , and theiameters  on the rφ and concrete cover of thickness The steel–concrete system composed of a rectangular concrete body 1 with a singular smooth rebar 2 of diameter ckness c  was consThe counter electrode 3, the reference electrode 4, and the working electrode 2 that was a steel rebar, formed a three-electrode system that was connected to the potentiostat.CPE, described by the parameters CPE  is determined using the algorithms of the Gaussian method for estimating the volume for a triple integral [3, whereas the volume of the solid element was expressed as the quotient of the dry concrete mass Definitions of local coefficients of concrete and steel geometry were introduced to map the irregular geometry of the flow area of polarization currents between the counter electrode 3 and the working electrode 2 in the he paper .(1)γi,juctivity b, given integral . The solD. The approximated value of that integral was determined using the algorithms of the Gaussian method for estimating the volume for a double integral [D with a surface area of The local coefficient for steel geometry he paper (6)γi,jsectrical b. The suintegral . The flation cf. . ParametFinally, the defined local coefficients of concrete steel γs 3D model. The total equivalent impedance They comprehensively describe the flow area of polarization currents between the counter electrode 3 and the working electrode 2 with reference to geometry of that area. The representative form of the expressions (7) resulted from two planes of symmetry included in the concrete  is given3D model were divided into two stages. At first, assumptions made for the 3D model were empirically verified with reference to the impact of the rectangular geometry of the counter electrode on shapes of impedance spectra.Experimental tests related to the computational analysis with the S1 and S2. Concrete mix S1 with the ratio of w/c = 0.43 was prepared from 489 kg/m3 of Portland cement 32.5R, 501 kg/m3 of fine aggregate with fraction to 2 mm, 1168 kg/m3 of coarse aggregate with fraction of 2–8 mm, and 212 L/m3 of water. Another mixture S2 differed from the mixture S1 only in the presence of an additive in the form of 3% NaCl dissolved in batched water. Smooth rebars with a diameter φ12 mm and φ16 mm, which were made from stainless steel of grade S235JR, were used as reinforcement in concrete elements. Test elements were prepared from two concrete mixes, –/AgCl,Ag electrode was used as the reference electrode.The three-electrode system for the EIS measurements on reinforced concrete elements was prepared from a set of rectangular counter electrodes cut from a stainless steel sheet of grade X5CrNi18-9 . The couThe photo of a test stand for performing impedance tests on the impact of the rectangular counter electrode width on the shape of impedance spectra of steel in concrete is shown in S1, which is characterized by high protective properties against steel. Two other elements were also made from concrete of series S2 (with chloride additives) with reduced protective properties.The impact of width In accordance with the assumptions described in point 2, the test stand shown in 5 on each side to minimize the effect of a gradual change in moisture content in concrete cover.The working electrode in each case was the rebar 1 in concrete element, and the counter electrode 2 and the reference electrode 3, which were placed on the top surface of concrete through wet felt 6 to provide electric contact. Moisture content in concrete cover was measured with the dielectric method prior to each impedance measurement. The obtained results and the methodology for converting dielectric moisture into mass moisture are presented in LM1, LM3 and LM5), which were selected from analysed five models presented in 4 between the counter electrode 2 and the working electrode 1. Hence, the flow of alternating current through concrete during the impedance measurements was maximal at the longest counter electrode, and minimal at the shortest one. Similarly, BM1, BM3 and BM5) of the three-electrode system, representing the test stand from 3D model assumptions describe in point 2 and to empirical equations given in Three characteristic models  in terms of the impact of a changing length S1 was within a range of 5.8–21.5 kΩ  on the Nyquist plots –(10) electrochemical parameters determined from S1 obtained from the counter electrodes of EL = 200, 150, 100 and 50 mm in length, at the average mass moisture of concrete midw = 4.8%. The spectra in S2 corresponding to the following lengths: EL = 246, 200, 150 and 50 mm, obtained at the measured average moisture content in concrete midw = 5.0%—cf. Dashed lines in LM2, LM3, LM4 and LM5 of the test element of series S1, while spectra LM1, LM2, LM3 and LM5 in S2. As in the previous analysis of the impact of the counter electrode width, the adjusted model spectra are additionally shown on the Bode plots—Δw in moisture content against mass moisture, at which the initial spectra LM1 and LM4 were obtained. An increase in moisture content in concrete element of series S1 was observed within a relatively narrow range of +0.2–+0.9%, whereas moisture content in concrete of series S2 was close to the absolute value and ranged from −0.1 to 0.9%. As in the case of analysing the impact of the counter electrode width, the non-uniform moisture content in concrete was the reason for varying theoretical values of average moisture content in concrete per the element volume. In relation to the simulated distribution of current lines shown in The solid line in 3D model-based simulation of effects on the impedance shapes produced by the reinforcement diameter and length, concrete cover, and limited polarization range forced by an electrical insulator. The experimental verification presented in S1, an elongated test element with the dimensions of 1000 × 100 × 56 mm was prepared That element was reinforced with a bar φ16 mm, 1030 mm long, made of smooth steel of S235JR grade. A substantial length of the reinforced concrete element, in the context of the electrochemical tests, was to simulate measurements on real elements from concrete structures under laboratory conditions. Additionally, this element could prevent polarization of the whole rebar covered with concrete at the considerably small size of the counter electrode. Otherwise, the method functionality could not be effectively assessed.For the purpose of showing the functionality of the elaborated iterative method of determining polarized area of reinforcement in concrete of series Gamry Reference 600, which was used in the testing procedure for measuring impedance at a rage of frequencies of 1 mHz–1 MHz at the potential amplitude 20 mV in potentiostatic mode.A view of the test stand for impedance measurements of long test elements 1 is presented in The EIS measurements were taken for comparative analysis of two counter electrodes with a length of Electrochemical parameters of the model were determined in the first stage of tests using the equivalent electrical circuit, as shown in In the second stage, these Formulas (1)–(7) were used to calculate local and global coefficients of concrete and steel geometry, for which lengths of polarization ranges The coefficient 3D model for the shorter counter electrode The selected values of the coefficient Regarding the corrosion evaluation of reinforced concrete, density of corrosion current Equation ,60 was unsfer Rt . The coeto 52 mV ,62,63,642, and for the longer one was 2. As can be seen, the values Taking into account the above assumptions and substituting values of the charge transfer resistance To summarise the above iterative procedure for determining the polarized area of reinforcement during the measurements on reinforced concrete corrosions by the EIS method, the schematic presentation of key elements and stages of this methodology are shown in 3D model, which could include and separate at the analysis stage features of impedance spectra not related to electrochemical effects. The development of an iterative methodology for determining the polarized area of reinforcement in a single rebar in concrete highlighted the practical functionality of the model.This paper supplements multi-thread experimental tests that verify the original 3D model was to define the area of electrically conductive concrete within the developed three-electrode system (with a rebar as the working electrode) and route theoretical paths of current in that area. Basic equivalent electrical circuits, which were connected in parallel, were assigned to each current path, which was a curved block of concrete between the counter electrode and the working electrode. By introducing the geometric coefficient for concrete and steel into Formulas expressing the overall impedance of the system, electrochemical parameters of equivalent circuits were coupled with geometric parameters.A novelty of the experimentally verified 3D model. The future transition into solutions related to the method of finite elements would lead to increased accuracy of modelling the steel-concrete systems; however, it will be a difficult task.Relying on empirical Formulas  to deter3D model; that is, the dimensions of the rectangular counter electrode. Other geometric parameters of the analysed steel-concrete system; that is, a diameter and length of the rebar, thickness of the cover, and polarization range, have already been positively verified and documented in the papers [Results of impedance tests described in this paper referred to the experimental verification of the final, not tested up to then, geometric parameter of the e papers ,55,56,573D model represented tendencies for impedance shapes to change, which was observed during the EIS measurements. However, a slight adjustment of model spectra by a relevant selection of the theoretical moisture content in concrete had a significant impact on the matching degree.The discussed impedance tests performed for different widths and lengths of the rectangular counter electrode indicated a strong relationship between the spectra shapes and variable geometry of the analysed steel-concrete system. The verified The tests employed a simplified method of measuring moisture content in concrete with a dielectric method and converting this parameter into mass moisture . If the 3D model and the relevant formulas. Hence, a description of this method required a complex presentation of the model (The main objective of this paper was to present and experimentally verify the original iterative method for determining the polarized area of reinforcement in concrete. Based on the developed methodology, the initial matching degree of model spectra to the empirical spectra was he model . 3D model, was found to be important in this paper.The iterative method for determining the reinforcement polarization involved the use of a single counter electrode in the three-electrode system and the possible identification of the test area, including electrochemical parameters obtained from a single EIS measurement. Therefore, the experimental tests to verify the simulated impact of varying sizes of the counter electrodes on the spectra shapes, based on the It is difficult to compare this new method of determining polarization surface of reinforcement in concrete with other methods that include the analysed surface in measurements of the reinforcement corrosion rate, which were specified in the Introduction section, in a measurable way without additional tests. The proposed approach seems to be closest to a common solution based on measurements using a counter electrode with guard ring.Looking ahead to further developments of this model to associate it with the method of finite elements, there is the possibility of implementing the described algorithms into the software of testing devices that could be used to provide a more precise in situ evaluation of risk corrosion of reinforcement in concrete.


The purpose of this article is to determine the effect of granite powder grain size and grinding time on the properties of cement paste. A series of cement pastes modified by the addition of granite powder were made and the properties of the fresh mixtures and the mechanical properties of hardened pastes were studied. Based on the study, the best results, from the point of view of the application of granite powder in cementitious composites, were obtained for a sample with granite powder ground for 3 h, in which 50% of the particles were smaller than 4 μm, and 90% were below 20 μm. Compressive strength of 55 MPa and flexural strength of 6.8 MPa were obtained on this sample after aging for 28 days. To confirm the validity of using granite powder as substitute materials, additional tests such as scanning microscopy with elemental analysis  and infrared (FTIR) studies were performed. One trend in the development of the modern construction industry is their transition to cost-effective production technologies, while ensuring the high quality of building materials and structures. Currently, there is a significant increase in the use of industrial waste, caused by the sharp rise in energy prices and the need to expand the raw material base. This trend is noticeable worldwide ,2. PortlWhen looking for opportunities to improve the environment, it is important to test alternative material solutions . It is observed that the addition of granite powder can reduce the cement content of mixtures. The paste substitution method has been found to be a promising way to produce high-performance eco-friendly composites, and also contributes to higher waste utilization and lower cement content ,7,8,9,10There are new methods for advanced processing of industrial sludge using a closed-cycle drying process. These methods contribute to increasing the amount of hazardous waste used in the production of construction materials ,18,19,20The authors of this publication conducted a study on the effect of granite powder granulation on the mechanical parameters and microstructure of cementitious composites. The proper granite powder fineness and surface development has an impact on the reactions taking place in the cement paste and, consequently, on its parameters. A novelty is the subject of grinding granite powder to optimize the properties of the mixture and cementitious composite.A fine granite fraction with the chemical composition presented in A study of the granite grinding process in a ball mill has been carried out . The balSamples with grinding times of 1, 3 and 5 h were selected for further testing. For comparison purposes, a reference paste and those with granite powder without grinding were also made.To compare the effect of time of grinding of granite powder on the properties of cementitious composites modified with this powder, we prepared five series of cementitious pastes. The reference series was prepared with only 100% cement . In the other series, we replaced 20% of the amount of cement in the mix with the addition of prepared granite powder. The name GP0H describes granite powder without any grinding , for other granite powders  we used a grinding technique to achieve more fine grains of powder—we ground GP 1, 3 or 5 h (those numbers are the names of each sample of GP). Detailed compositions of each research series are presented in To prepare samples of cementitious pastes modified with the addition of ground granite powder, we used the typical mixing procedure described in EN 1015-3 . In the Due to the limited scope of wet sieve analysis, a laser particle meter was used to measure the grain distribution of granite powders, using the Malvern Master Sizer 2000 . In the laser analyzer, the laser light beam shining through the measuring cell was diffracted onto the particles in proportion to their size. When the laser light encountered a population of grains, the volumetric distribution of their size was expressed by the intensity of the distribution of light diffracted on them. According to the principle of diffraction, small particles refract the light of the laser beam at larger angles, and larger particles are the source of smaller angles of deviation from the axis of the light stream, while the intensity of the light stream is proportional to the content (number) of individual particles. The resulting diffraction image is identified by an array of light-sensitive detectors, and the resulting signals are used to calculate the grain size distribution. To investigate the consistency of cementitious pastes we used the slump spread method. This method was conducted based on the EN 1015-3 standard . We castaW) of the samples, they were placed in water and then weighed every 24 h to determine when the samples were fully saturated (difference in sample weight <1.0%). After determining the amount of water absorbed by the samples, water absorption was calculated. Water absorption was determined from the weight of the dry sample (dm) and the weight of the wet sample (wm) according to the following formula:The basic physical properties of cement pastes, such as bulk density, porosity and water absorption, were determined. The tests were carried out in accordance with the requirements specified in the procedure PN-B-04500:1985 . DetermivP) was determined from the ratio of the volume of air pores (pV) in the test material to the volume (V) of the test sample based on the equation:Volumetric porosity . This microscope allows operation under high vacuum and operation with steam as the working gas in low vacuum mode (10–200 Pa). The magnifications achievable are from 100× to 1,000,000×. The microscope allows evaluation of material surfaces, internal structure, changes and deformations. In addition, the microscope is equipped with an EDS Octan Elect X-ray energy-dispersive spectrometer from EDAX , thanks to which it is possible to quickly analyze the chemical composition and determine the elements  of selected micro-areas on the surface of the sample, including those too small for examination by other methods. The method was used for illustrative purposes and the chemical compositions referred to the measurement site from which the data were collected.−1. The diffuse reflectance technique was utilized, in which the incident beam was allowed to be reflected off the ground sample towards an overhead mirror upon which the diffusely scattered rays were collected and measured in the detector.The spectrometer used was a Bruker Vertex 70 v  with an insert cell for diffuse reflectance spectroscopy. The measurement range lies between 400 and 4000 cmSince a sieve smaller than 0.02 mm was not used for sieve analysis due to technical limitations, and the grain composition curves of grinding samples at times 3, 4 and 5 h practically overlap , a more The goal of grinding granite was to achieve the most developed specific surface of the material. By reducing the particle size, we achieved greater reactivity and the ability to form cementitious phases. pV) and water absorption (aW) of cured cement composites. Mortar with the addition of unground granite powder has a higher volumetric porosity (by about 1.5%), and water absorption (by about 2%) than the reference mortar. The values of these parameters decrease with the grinding time of granite powder; the most favorable results were obtained for a grinding time of 3 h, that is, pV of 8.5%, and aW of about 6.2%.The addition of granite powder increases the density of the mixture by an average of 5%, with the density increasing slightly as the grinding time of the powder increases. This is due to the development of the surface, a higher degree of fineness and the filling of small pores by micro-particles of rock. This phenomenon applies both to the fresh mixture and after hardening. The differences in physical properties may be related to the fact that granite wastes differ significantly in terms of grain structure and parameters describing their surface morphology. In addition, there is a significant difference in the development of their surface (grinding time of samples) ,32,33,34Determination of the basic mechanical properties of cement pastes consisted of destructive tests—the compressive strength test and flexural strength test at the appropriate time  after the samples were formed. 3S) and belite (C2S), forms massive, hexagonal crystals , which is well-detected by a definite unique peak at 3640 cm−1. This method is also used to study the bands assigned to calcium silicate hydrate (C-S-H) as a function of curing and aging conditions [FT-IR spectroscopy readily highlights the presence of portlandite (Ca(OH)nditions ,36. Figu−1. During aging and decalcification, these IR bands shift depending on the silica polymerization process. Assignment of the others did not show specific hydration perturbations: portlandite was detected at 3642 cm−1 (O-H stretching vibrations); C-S-H was characterized by main bands at 973 cm−1 (asymmetric Si-O stretching vibrations); for ettringite, a characteristic band was detected for O-H-1640 cm-1, and Al-O 874 cm−1. Peaks from S–O bonds fall at 1150-1100 cm−1 and overlap with Si-O vibrations for the C-S-H phase. The FTIR spectroscopy also highlighted the presence of CaCO3 . The detection of CaCO3 was assigned to the carbonation process [The main characteristic C-S-H peaks are located between 1100 and 900 cm process . 3S-(3CaO·SiO2); belite-C2S-(2CaO·SiO2); tricalcium aluminate-C3A-(3CaO·Al2O3); braunmillerite-C4AF-(4CaO·Al2O3·Fe2O3); calcium oxide (free)-CaO, anhydrite-(CaSO4·0.5H2O) [Cementitious composite systems from an application point of view can be reduced to a mixture of three components: cement; fine aggregate (powders) and water. It is a composite system in which aggregate grains are surrounded by hardened cement paste. The formation of mortar is determined by the hydration reactions of the cement. Cement is a mixture of solid phases containing primarily various types of calcium aluminates and aluminosilicates. In particular, it is: allite-C·0.5H2O) . The pro2 in its composition. Its fineness can significantly affect the formation of ettringite crystals [2 ;The introduction of milled  granite filler reduces the total pore volume, and reduces water absorption and penetration;An increase in the compressive strength of samples with the addition of finely ground granite compared to unground granite is observed;Images of the microstructure of cement paste with granite powder obtained by scanning microscopy indicate that the small particles act as crystallization centers, i.e., accelerate the initial stage of chemical curing.Based on the results of cementitious composites modified with granite powder, the following conclusions were made:


This study used a retrospective method to explore the relevant factors affecting the prognosis of periodontal-endodontic combined lesions.  According to the changes of subjective feelings and clinical indicators of affected teeth, selected patients were divided into an effective group and an ineffective group. The natural conditions  of the patients and various clinical indicators at the initial and follow-up visits were collected, including the periodontal clinical indicators of the whole mouth and the clinical indicators of the affected teeth. The full-mouth periodontal clinical indicators include periodontal probing depth (PD), clinical attachment loss (CAL), sulcus bleeding index (SBI), and simplified oral hygiene index (OHI.S); clinical indicators of affected teeth include PD, CAL, SBI, mobility (TM), clinical crown-to-root ratio (CR), periapical index (PAI), and number of root canals. P < 0.05). At the initial diagnosis, there was no significant difference in the clinical indicators of the whole mouth between the effective group and the ineffective group. After a combined endodontic treatment, the clinical indicators of the two groups were significantly improved (P < 0.01). There was no significant difference in other periodontal clinical indicators between the two groups.  There were 74 cases of endodontic combined treatment, with a total of 86 teeth. There was no significant difference in age and gender ratio between the effective group and the ineffective group, and the proportion of smoking patients in the ineffective group was significantly higher than that in the effective group ( The prognosis of nonsurgical treatment of periodontal and periodontal combined lesions is mainly correlated to the patient's oral hygiene maintenance, as well as the loss of attachment, the degree of loosening, the clinical crown-to-root ratio, the periapical index, and the number of root canals. Periodontal and endodontic lesions (PEL) is mostly caused by bacterial infection that leads to the destruction of periodontal tissues and pulp tissues , 2. It iThe PEL involves both pulp tissues and periodontal tissues. Limited by the relative backwardness of diagnostic approaches, clinicians generally make a rough and preliminary judgment on the prognosis of PELs through their own practical experience at the current stage. The clinical manifestations of the PPD are diverse and complex; thus, the experience of clinicians alone is far from enough. Therefore, the determination of the prognosis of an individual patient must be based on the study of the prognosis of the disease group, and the research data of the large sample of the disease should be used as the premise, so as to make a scientific expectation of its prognosis .In this study, a retrospective study method was used to collect the data and various clinical indicators of patients at the initial diagnosis and follow-up, to explore the relevant factors affecting the prognosis of PEL and to guide the prognosis judgment and treatment of PEL. The program has certain clinical significance.72 cases of PEL were collected from December 2018 to December 2021, with a total of 86 teeth. The patient selection process is shown in α = 0.05, the test power was 0.8, and the confidence level was 95% as shown in Patients including 42 males with 50 teeth and 32 females with 36 teeth. Patients were aged 24–66 years. The sample size of this experiment was determined by the sample size and power calculator, where the test level was two-sided The inclusion criteria for this study were as follows: (1) At the initial visit, the diagnosis was a case of PEL and the diagnosis was confirmed after treatment; (2) complete the relevant periodontal. The procedure of combined endodontic treatment: supragingival ultrasonic scaling at the initial visit, root canal treatment a week later, subgingival scaling and root planing 1 week after the completion of root canal treatment (two times), and periodontal maintenance treatment at the later stage; and (3) the disease records should be complete and should have various clinical indicators at the initial diagnosis, full-mouth curved body slices and root apical films of the affected teeth; various clinical indicators at 1, 3, and 6 months of follow-up after combined treatment, and 3 months after root canal treatment and 6-month-old periapical slices.The exclusion criteria for this study were as follows: (1) abnormal tooth anatomy; (2) received periodontal treatment in the past 6 months before the initial visit; (3) take antibiotics or non-steroidal drugs in the past 3 months before the initial diagnosis; (4) related systemic diseases, such as hypertension, diabetes, and liver and kidney diseases; and (5) those who have incomplete records of relevant information in the chronicle of serious diseases.From the included patients, the clinical indicators of the patients were followed up for 1 month, 3 months and 6 months after endodontic treatment, including the periodontal clinical indicators of the whole mouth and the related indicators of the affected teeth. The periodontal clinical indicators of the whole mouth include PD, CAL, SBI and OHI-S; the periodontal indicators of the affected teeth include PD, CAL, SBI and TM; x-rays were taken 3 months and 6 months after the initial diagnosis and combined treatment, respectively The CR and PAI of the tooth were read from the X-ray film; the number of root canals of the tooth was mainly determined by root canal treatment（We probe to the gingival sulcus floor or cementum enamel boundary with a periodontal probe and record the mesial and middle of the labial  side of each tooth PD, CAL, and SBI at 6 sites of central, distal, and lingual  side mesial, central, and distal. Sulcus bleeding index (SBI): O = no bleeding on probing, healthy appearance of gingival margin and papilla; 1 = no bleeding on probing, but mild inflammation of gingival margin and papilla; 2 = point bleeding after probing; 3 = linear bleeding after probing, blood spilling in the gingival sulcus; 4 = bleeding after probing, blood spilling out of the gingival sulcus; 5 = bleeding or spontaneous bleeding after probing. Looseness (TM): According to the loosening direction of the teeth, the looseness in the buccal/labiolingual direction is grade I, the loosening in the buccal/labiolingual and mesiodistal directions is grade II, and the loosening in the buccal/labiolingual, mesiodistal and vertical directions is grade II degree III.l = less than 1/3 of the tooth surface; 2 = between 1/3 and 2/3 of the tooth surface; 3 = more than 2/3 of the tooth surface. CI-S: 0 = no calculus above and below the gum; 1 = the calculus above the gingival occupies less than 1/3 of the tooth surface; 2 = the calculus above the gingival occupies between 1/3 and 2/3 of the tooth surface, or there is scattered subgingival calculus; 3 = supragingival calculus occupies more than 2/3 of the tooth surface, or there is continuous and thick subgingival calculus.Simplified Oral Hygiene Index (OHI.S): The value is 0∼6, we check the labial  surface of 16, 1l, 26, 3l and the lingual surface of 36, 46, including the simplified soft scale index (DI.S) and simplified calculus index (CI-S). DI. S: 0 = no soft scale on the tooth surface; Clinical crown-to-root ratio (CR): The ratio of the lengths of the suprabone and infrabone teeth based on the apical radiograph of the affected tooth, with the horizontal line of the lowest point of the alveolar bone as the boundary.Periapical index (PAI): According to the periapical film of the affected tooth, it is divided into grades 0–5, 0 = normal periapical bone density and no light-transmitting area; 1 = periapical light-transmitting area diameter of 0.5–1 mm; 2 = diameter of periapical light transmission area 1–2 mm; 3 = diameter of periapical light transmission area of 2–4 mm; 4 = diameter of periapical light transmission area of 4–8 mm; and 5 = periapical penetration The diameter of the light area is greater than 8 mm.Compared with the initial diagnosis, according to periodontal, the changes of patients' subjective feelings, and clinical indicators during the follow-up visit after combined endodontic treatment, the curative effect was divided into 3 groups .t test was used to compare the differences in gender and smoking status of the patients between the two groups, the repeated measures analysis of variance was used to compare the differences in the clinical indicators of the full-mouth periodontium at different time points between the effective group and the ineffective group, and the independent samples t test was used to compare the differences of the patients between the two groups. There was no difference in age between the two groups.SPSS 21.0 software was used to analyze the natural conditions  and various clinical indicators of the patients between the two groups. The P < 0.05, In this study, PD, CAL, SBI, and TM of the teeth at the initial visit were selected as periodontal observation indicators. There was no significant difference in PD between the effective teeth and the invalid teeth. Observation indicators including CAL, SBI, and TM were higher in the invalid teeth than in the effective teeth, and the difference was statistically significant , and the difference was statistically significant.The number of root canals in the affected tooth was determined by X-ray and root canal treatment. The average number of root canals of invalid teeth was more than that of valid teeth (P < 0.01), but the OHI of invalid teeth. S was larger than the effective teeth, and the difference was statistically significant (P < 0.05). There was no statistical difference in other indicators  between the two groups.All patients received a comprehensive periodontal system examination at the initial diagnosis, 3 months, and 6 months after the completion of the combined treatment, respectively. The comparison of the periodontal clinical indicators of the effective teeth and invalid teeth at the initial diagnosis and 3 months and 6 months after the treatment is shown in This study retrospectively included 74 patients with combined endodontic treatment with a total of 86 teeth. The patients were divided into an effective group and an ineffective group according to the subjective feelings of the affected teeth and the changes of clinical indicators. The natural status  and various clinical indicators of the patients at the initial diagnosis and follow-up were collected, including the periodontal clinical indicators of the whole mouth and the clinical indicators of the affected teeth. Full-mouth periodontal clinical indicators include periodontal probing depth (PD), clinical attachment loss (CAL), sulcus bleeding index (SBI), and simplified oral hygiene index (OHI.S); clinical indicators of affected teeth include PD, CAL, SBI, range of motion (TM), clinical crown-to-root ratio (CR), periapical index (PAI), and number of root canals.PD, CAL, and SBI are objective indicators reflecting the activity of periodontal inflammation and the damage and repair of periodontal tissue, an increase in these indicators represents the severity of PEL , 12, whiThe degree of periodontal tissue destruction of the affected tooth has a significant impact on the prognosis of PEL. PEL are mostly derived from moderate to severe periodontitis , 16. SomTo sum up, the prognostic factors of PEL mainly include smoking and oral hygiene maintenance, loss of attachment, looseness, and clinical crown of the tooth. The root ratio, periapical index, and the number of root canals, as well as the doctor, can make a prognosis judgment on the affected tooth according to the specific situation of the patient, and make a targeted treatment plan considering the patient's wishes. Looking back at the development of medical care in recent years, the gradual deepening of PEL-related research studies, as well as the development and practicality of new drugs, has effectively improved the occurrence of oral diseases. In the field of medical practice, it is the focus of clinicians to make appropriate adjustments or updates to existing preventive methods, improve the patient's internal environment stability as much as possible, and reduce and eliminate adverse effects caused by PEL. It is also the focus of academic research and is an important direction.The limitation of this study was as follows: we only included the teeth with clear periodontal and pulpal inflammation, blaming the difficulty in accurate diagnosis of periodontal and endodontic lesions. With the advancement of related technologies, more accurate diagnostic tools may be available in the future, which will benefit the accurate treatment of the symptoms of this disease, so that we can further include more manifestations of the affected teeth as samples for better correlation analyses. Although the subjective teeth without clear symptoms and clinical manifestations of pulpitis were not included, we still consider that the results of this paper have certain guiding significance for doctors to determine the prognosis of teeth with PEL.The prognosis of nonsurgical treatment of periodontal and periodontal combined lesions is mainly related to the patient's oral hygiene maintenance, as well as the loss of attachment, the degree of loosening, the clinical crown-to-root ratio, the periapical index, and the number of root canals .