Patients with chronic back pain as a result of degenerated disc disease, besides pain, also present with impaired gait. The purpose of the article was to evaluate kinetic and kinematic characteristics during gait analysis in patients with chronic low back pain as a result of degenerated disc disease, before and after the application of physiotherapy, including manual therapy techniques. Seventy-five patients suffering from chronic low back pain were randomly divided into 3 groups of 25 each. Each group received five sessions (one per week) of interventions with the first group receiving manual therapy treatment, the second a sham treatment and the third, classic physiotherapy . The effectiveness of each treatment was evaluated using an optoelectronic system for recording and analysis of gait (kinetic and kinematic data). Patients overall showed an impaired gait pattern with a difference in kinetic and kinematic data between the left and the right side. Following the application of the above-named interventions, only the group that received manual therapy showed a tendency towards symmetry between the right and left side. In patients suffering from chronic low back pain as a result of degenerated disc disease, the application of five manual therapy sessions seems to produce a tendency towards symmetry in gait. Gait is the most common form of human movement and often appears altered in low back pain patients ,4,5,6,7.A number of studies done on back pain and gait have attempted to evaluate the effect of the pain location  on gait in patients with low back pain . The resPhysiotherapy seems to have an ambiguous effect on chronic low back pain and especially pain and disability levels, spinal range of movement and paraspinal muscle activity. The use of modalities  ,33,34,35Thus, the purpose of this study was the evaluation of gait kinetic and kinematic characteristics in chronic low back pain patients suffering from degenerative disc disease, before and after the application of manual therapy techniques. We hypothesized that manual therapy could improve gait characteristics and render it more symmetrical.https://clinicaltrials.gov/, NCT02645123, accessed on 12 June 2021). Recruitment and trials took place between October 2013 and May 2015. The study was approved by the ethics committee of the Technological Education Institution of Central Greece (32/6-3-2013) and all volunteers signed an informed consent form before their participation in the study. The study involved 75 patients, 42 male and 33 female, with an age range of 21 to 78 years. To estimate the number of participants, a statistical power software  [This was a randomized sham-controlled trial, part of a larger research project and the full trial protocol was registered at an international clinical trial database (3.1.9.2) . The exc3.1.9.2) .The materials used were: (1) One electrically-operated plinth ; (2) Weight measuring scale ; (3) Height measuring system ; (4) Two force platforms embedded on a specially formed floor to prevent movement ; (5) Measuring tape ; (6) Skin marker ; (7) A three-dimensional gait analysis system utilizing 6 specially made cameras ; (8) Twenty-nine spherical reflective markers (diameter 12 mm) attached by means of a double sided hypo-allergenic tape  on predefined spots; (9) A metronome  to control gait speed and posterior to anterior mobilization frequency; (10) A watch  to measure the therapy time; (11) Three personal computers. The first had the Bioware software installed , which analyzed and transferred the signal from the force platform to the second computer; the second had the software Cortex, KinTools RT, Skeleton Βuilder, Calcium Solver, Sky Scripting, DV Reference installed , which, in combination with the signal received from the force platforms, recorded and analyzed both kinetic an kinematic data from the gait trials; and the third had the statistical software SPSS, 21st edition , Excel  and G* power analysis software  installed.All experimental procedures took place at the Biomechanics laboratory of the Technological Educational Institution of Central Greece  and wereEach volunteer was asked to remove their shoes and clothes up to their underwear, and then their height and weight were measured in order for the data to be put into the gait analysis software. Then, the 29 spherical markers were placed at points designated by the gait analysis system manufacturer . Out of The gait analysis system was calibrated on every trial day by means of a calibration wand and an L-shaped frame, both of which were precision-made and included spherical markers at an exact distance. These devices were either placed statically on the force platform (L-frame), or someone was moving them within the measurement space . The global coordinate system was used for reference and the direction of movement was defined as the x-axis, whereas the y-axis was lateral and the z-axis was vertical towards the ceiling.The next step was to record the static position of the participant as shown in This acquisition was necessary in order for the gait analysis software to calculate the joint centers. The sampling frequency for both static and dynamic acquisitions was set at 120 Hz. The static positioning recording was set to one second. Then the recording was processed and filed with a numerical name that only the researcher was aware of in order to protect the personal data of each participant. If the recording was adequate and there was no occlusion of a marker, it was followed by the gait recording .Each participant walked 10 times in one direction (X axis). The pace was set at 110 steps/minute according to the metronome and was common for all participants. The pace was chosen based on measurements of a normal population ,48 and w(1)Τ1: moment of peak value of ground reacting force (F1) during heel strike;(2)Τ2: moment of minimum value of ground reacting force (F2) during mid stance;(3)Τ3: moment of peak value of ground reacting force (F3) during acceleration .The first recording was taken right before the first intervention and the second recording was taken just after the last intervention (5 weeks later). The gait analysis software processed the data (kinetic and kinematic) for each participant, and for the purposes of statistical analysis, the mean values from the 10 gait recordings were calculated and chosen. From the biomechanical data of a walking cycle and for statistical use, 6 time points were selected, 3 during the right foot contact and 3 during the left . These tAt those 6 points (left and right together), the values of the vertical ground reaction force and the position of the trunk and pelvis in all three planes were recorded. These values were used for statistical comparison before and after intervention in the same group and between groups. The trunk was assessed as a compact structure starting from the 7th cervical vertebra and ending in the 5th lumbar vertebra .The participants were randomly allocated into three groups of 25 patients each: the Manual Therapy (MT), the Sham Treatment (ST) and the Conventional Physiotherapy (CP) group. The randomization process was achieved using the internet-based software Graphpad . The parThe MT group was treated by using manual therapy techniques  ,54,55 onIn the sham treatment group, the investigator just touched the skin overlying the lumbar spine for 10 min and did not make any other intervention (one session per week).In the conventional physiotherapy group, the investigator applied exercise (static stretching of the hamstring muscles of both lower limbs for 5 min—5 sets × 1 min each) , transcuAll interventions were performed by one physiotherapist with 21 years of experience in physiotherapy, 15 of which were in manual therapy.t-test was used to assess differences before and after the intervention on each group, and the ANCOVA was used among the groups. The significance level for all statistical comparisons was set at p < 0.05. The data were analyzed using the statistical package for social sciences .Data normality was tested using the Kolmogorov−Smirnov statistical test. For the descriptive statistics, the mean (M) was used as an indicator of central tendency and the standard deviation (SD) as a dispersion index. The differences among the three groups in anthropometric characteristics and baseline measurements of the dependent variables were tested using the statistical test of the analysis of variance (one-way ANOVA) checking the homogeneity with the Levene test. The comparison in the efficacy of the three treatments  was performed with the analysis of covariance (ANCOVA), using as a covariance factor the baseline values of each dependent variable and comparing them to the values of the same variables among the different groups after treatment application . When a No participant was excluded, and all analyses were performed on the original groups. Anthropometric characteristics of all groups, pre- and post-intervention pain levels and the mean value of the degree of disk degeneration are summarized in From the analysis of covariance (ANCOVA), MT techniques appear to produce statistically significant differences in 25 of the 42 pairs (before-after) of the dependent variables. t-test which compared the ratios between left and right sides before and after for each group, statistically significant differences were found for very few ratios. In the MT group, differences (p < 0.05) were observed for the trunk at the frontal plane at all three moments  as well as for the pelvis position at the transverse and frontal planes at moments T2 and T3, respectively. In the ST group, differences (p < 0.05) were observed in the GRF at all three moments—in the trunk position at the transverse plane at moment T1 and in the pelvis position at the frontal plane at moment T2. For the classical physiotherapy group, a difference (p < 0.05) was only observed for the GRF at moment T1. From the results of the ANCOVA test, differences (p < 0.05) between the groups were observed in only four dependent variables. Overall, for the MT group, 14 of the 21 ratios were within the margin of symmetry, with 10 of the 21 ratios for the ST group and 10 of the 21 for the CP group. These are summarized in Based on the results of the 1 is partially accepted.Although manual therapy techniques are widely used in the management of patients with chronic low back pain, there is relatively little research about their effectiveness in the clinical presentation of patients or their mechanism of action . The aimThe application of ST showed statistically significant differences in most kinetic and kinematic characteristics of the gait, while the application of classical physiotherapy showed statistically significant differences in some kinetic and kinematics characteristics. Regarding symmetry, from the MT group, 14 of the 21 ratios were within the margin of symmetry, along with 10 of the 21 ratios for the ST group and 10 of the 21 for the CP group. The 0.3 numerical distance from 1, which is indicative of absolute symmetry, is suggested in this article as a way of assessing the asymmetry following each intervention. More research on this matter will reveal the clinical value of this choice.N = 75), there appears to be a gait asymmetry between the right and left sides both in the GRF and in the position of the trunk and pelvis at each measured time point. These results are in agreement with Taylor et al. [Based on the kinetic and kinematic analysis of the patients who participated in the study  in 22 out of a total of 45 pairs of dependent variables related to the kinetic and kinematic characteristics of gait. There is evidence to suggest that the application of posterior to anterior forces on the lumbar spine leads to a temporary decrease in the activity of the paraspinal muscles both in the area where the forces were applied and at a distance  [Gait differences in low back pain patients could also be attributed to the increased activity of paraspinal and abdominal muscles ,64 or toections) . Similarections)  cannot bA decrease in paraspinal muscle activity following spinal manipulation was also observed by Harvey and Descarreaux . HoweverRegarding the limitations of the study, according to Bourne et al. the placement of markers on the skin might have introduced error in the measurements . AnotherThe gait of patients suffering from chronic low back pain as a result of degeneration of the intervertebral disc appears to be disturbed. An increased pelvic rotation and a reduced trunk rotation have been observed as well as a variation in the GRF. These changes may be due to the changes in proprioception of the lumbar region, the differentiation of motor control, the increased muscular activity of the paraspinal muscles, and the pain/posture avoidance. One clinically significant finding of this study is that the pain and disability level reduction observed in the MT and CP groups does not necessarily affect gait characteristics or symmetry, thus providing evidence against this notion.Following the application of five therapy sessions on the MT group, there was a tendency towards gait symmetry. It is likely that the effects of spinal mobilization are due to improved proprioception to changes in muscle activity and to the reduction of pain levels. Perhaps a combination of the above is most likely. However, a study that includes a homogenous age group while also assessing proprioception and paraspinal muscle activity could further shed light on gait adaptations due to chronic LBP and the effect of MT intervention.


The aim of the study was to evaluate the effectiveness of a new technology for the use of inhaled nitric oxide (NO) for the heart and lung protection during operations with cardiopulmonary bypass (СРВ).The study included 90 patients who underwent heart valve surgery and combined procedures under CPB and pharmacological cardioplegia. Three groups were created: group 1 ; group 2 (n=30) — NO inhalation (20 ppm) was conducted traditionally, that is, before and after CPB; group 3 (n=30) — NO inhalation was performed using a new technology — during the entire operation, with pulmonary artery perfusion and lung ventilation performed during CPB. Troponin I (cTn I) level, changes in the pulmonary function parameters, and clinical indicators were studied.Statistically significant lower levels of postoperative cTn I were registered in the patients of groups 2 and 3, at the same time, the levels were significantly lower in group 3 compared to group 2. The patients in group 1 (standardized anesthesia protocol) demonstrated an increase in the alveolar-arterial oxygen difference, an increase in intrapulmonary shunting, a decrease in blood oxygenation, and static lung compliance after СРВ. In both cases, NO inhalation retained the values of lung compliance and pulmonary oxygenating function after CPB, and in the patients of group 3, it also significantly reduced intrapulmonary shunting and alveolar-arterial difference after CPB. NO inhalation allowed a statistically significant decrease in the incidence of pulmonary dysfunction, acute respiratory failure, as well as the time of respiratory support in the ICU.The developed technology for the use of inhaled NO in surgery with CPB provides a clinically marked protective effect on the heart and lungs. The effectiveness of the protective action of NO depends on the duration of its administration and is most pronounced when used during the entire operation, including CPB time. The incidence of postoperative pulmonary complications after heart valve surgery is 8% , which iThe available experimental and clinical data suggest the ability of nitric oxide (NO) to reduce ischemia/ reperfusion injury of the heart –9 and luThe aim of this study was to evaluate the effectiveness of a new technology of using inhaled nitric oxide in protecting the heart and lungs during surgery with cardiopulmonary bypass.The present study is a single-center, randomized, prospective study. The work was carried out at the Privolzhsky Research Medical University on the basis of the Specialized Cardiosurgical Clinical Hospital named after Academician B.A. Korolev from September 2016 to September 2019. The study was conducted in accordance with the Helsinki Declaration (2013) and approved by the Ethics Committee of the Specialized Cardiosurgical Clinical Hospital named after Academician B.A. Korolev. The study included 90 patients of both sexes who underwent heart valve surgery and combined procedures under cardiopulmonary bypass. After the randomization of the study (the envelope method), three groups were created: in group 1 (n=30) — control group — a standardized anesthesia protocol and CPB were used; in group 2 (n=30), NO inhalation (20 ppm) was conducted before and after CPB; in group 3 (n=30), NO inhalation (20 ppm) was conducted during the entire operation, including the time period of CPB, at the same time, perfusion of the pulmonary artery and lung ventilation were also performed during CPB.The groups did not differ by the studied parameters. The demographic data of the patients, as well as their initial state, are presented in All the patients underwent preoperative preparation, then they underwent surgical interventions depending on the type of heart valve lesions and combined interventions under normothermic bypass and crystalloid cardioplegia . The types of the performed operations are presented in The main parameters of the surgery time period (CPB time and aortic cross-clamp time) in the patients of the three groups are presented in 2 concentration in the breathing mixture. Inhalation delivery of nitric oxide to the patients of groups 2 and 3 at the stages before and after CPB was performed to the inspiratory part of the breathing circuit. A special breathing system by Intersurgical (UK) was used for inhalation therapy. The gas flow of inhaled NO was 300–400 ml/min with a concentration of 23.70±0.62 ppm in the fresh oxygen flow, the total inhalation time being 2–4.5 h. The delivered inhalation mixture was monitored using an electrochemical NO/ NO2 analyzer. The average concentration of NO2 was 0.4–1.5 (0.90±0.07) ppm. The patients in group 3, simultaneously with inhalation of NO during CPB, underwent pulmonary artery perfusion with oxygenated blood, and low tidal volume ventilation [ For inhalation therapy, the Tianox apparatus  was used in all cases see the , which ptilation , 16. To study the effectiveness of the protective effect of inhaled NO on the heart, the troponin I (cTn I) levels were determined at different stages: 1) when the patient entered the operating room ; 2) 12 h after surgery; 3) 24 h after surgery; 4) 48 h after surgery. The study of troponin I in plasma was performed using the PATHFAST cTn I test system, designed for diagnostics on the PATHFAST analyzer .2 tension and inspired O2 concentration (PaO2/FiO2), alveolar-arterial oxygen difference (AaPO2), growth rate of intrapulmonary blood shunting (F-shunt). The given indicators were studied at the following stages: 1) initially, after tracheal intubation and the beginning of artificial lung ventilation (ALV); 2) before CPB; 3) after completion of CPB; 4) at the end of the operation, before transferring the patient to the ICU. In addition to these indicators, the following ones were studied: the nature of the postischemic recovery of cardiac activity; the vasoactive-inotropic score (VIS) dynamics; the incidence of postoperative pulmonary dysfunction detected at impaired gas exchange ); the incidence of acute respiratory failure (ARF); the duration of respiratory support from the moment the patient enters the ICU; the length of patient stay in the ICU; the presence of other postoperative complications , acute cerebrovascular accident, bleeding); hospital mortality.To assess the effectiveness of the protective effect of inhaled NO on the lungs, we studied the changes in the pulmonary function parameters: static lung compliance, the ratio of partial OStatistical analysis was performed using Microsoft Excel 2003, Biostatistics v. 4.03, and Statistica 6.0. The research results were processed in accordance with the rules of variation statistics. The distribution of the data was assessed using the Kolmogorov–Smirnov and Shapiro–Wilk tests. The arithmetic mean (M) and standard deviation (σ) were calculated for the data conforming to the law of normal distribution. The analysis of variance (ANOVA) was performed to check the reliability of differences between the mean values in the study groups by comparing the variances of these groups. When conducting pairwise multiple comparisons, the Newman–Keuls parametric test (ANOVA) was used for multiple comparisons [2 criterion. The results of all tests below the critical value, i.e. p≤0.05, were considered statistically significant.parisons . IntergrThere was no statistically significant difference in the parameters of cardiac recovery after cardioplegia in the patients of the study groups. Thus, the frequency of spontaneous recovery after removing the clamp from the aorta was 76.6% in the patients of group 1, 80.0% in the patients of group 2, and 83.3% in the patients of group 3.The effect of inhaled NO on the severity of myocardial contractile dysfunction was studied by the dynamics of the patients’ dependence on inotropic and vasopressor therapy and the level of cardiotonic support. No statistically significant difference in the VIS parameter after CPB and at the end of the operation in all the studied groups was detected.The change in the level of cTn I at the stages of the postoperative period is presented in Twelve hours after the operation, the patients of all the groups showed a statistically significant increase in the level of cTn I compared to the previous stage, while in the patients of groups 2 and 3 it was statistically significantly lower than in the patients of the group 1.Twenty four hours after surgery, there was a further decrease in the level of cTn I in all groups of the patients. At this stage of the study, no statistically significant differences were found in the patients of the study groups.Forty-eight hours after surgery, there was also a decrease in the level of cTn I in all groups of the patients: to 1.95±0.14 ng/ml in group 1, to 2.0±0.33 ng/ml in group 2, and up to 1.37±0.29 ng/ml in group 3. At this stage of the study, the level of cTn I was statistically significantly lower in the patients of group 3 compared to groups 1 and 2. There was no significant difference in this parameter between the patients of groups 1 and 2.Thus, this clinical study confirmed the presence of a protective effect of inhaled nitric oxide on the myocardium, which manifested itself in lower levels of postoperative cTn I in the patients of groups 2 and 3. A comparative evaluation of the effectiveness of the technology of using inhaled NO showed its advantage in the event of continuous use of NO (in the patients of group 3) in combination with pulmonary artery perfusion and ventilation during CPB.2/FiO2, static lung compliance are presented in The changes in the pulmonary function parameters of the lungs in the groups such as alveolar-arterial oxygen difference, F-shunt index, PaO2 index in the patients of all studied groups were noted. At the end of the operation, this indicator increased with statistical significance by 29.6 and 35.8% in groups 1 and 2, respectively . At this stage of the study, in intergroup comparison, the AaPO2 index was higher with statistical significance in the patients of group 2 compared with groups 1 and 3. There were no statistically significant changes in the AaPO2 index in the patients in group 3 at all stages of the study.After cardiopulmonary bypass, no statistically significant changes in the AaPOThe changes in the F-shunt index after CPB revealed a statistically significant increase from the initial one (by 40.7%) in the patients of group 1 with no significant changes in groups 2 and 3. At this stage, the values of the indicator in groups 2 and 3 were statistically significantly lower than in group 1. No significant difference was found in groups 2 and 3.At the end of the operation, an increase in the F-shunt index was noted in group 1 by 55.5% from thebaseline, in group 2 — by 42.3% and in group 3 — by 14%, the changes in the patients of groups 1 and 2 being statistically significant. At this stage of the study, in intergroup comparison, the F-shunt values in the patients of group 3 were statistically significantly lower than in the patients of groups 1 and 2. There was no statistically significant difference in the F-shunt values between groups 1 and 2. It is important to underline that there were no statistically significant changes in the F-shunt index in the patients of group 3 at all stages of the study.2/FiO2 indices after CPC revealed a statistically significant decrease in their values compared to the baseline in group 1 by 17.4%, while there were no significant changes in the patients of groups 2 and 3. In the intergroup comparison, no statistically significant differences were found between groups 2 and 3.The analysis of the PaO2/FiO2 in group 1 by 25.4% from the baseline, in group 2 — by 22.8%, and in group 3 — by 8.9%, and these changes were statistically significant in the patients of groups 1 and 2. In the intergroup comparison, there was no statistically significant difference between the patients of groups 1 and 2 as well as in groups 2 and 3, while at this stage the PaO2/FiO2 values in group 3 were statistically significantly higher than in group 1. It should be underlined that there were no statistically significant changes in the PaO2/FiO2 index in group 3 at all stages of the study.At the end of the operation, there was a decrease in PaOThe analysis of lung compliance after cardiopulmonary bypass revealed a statistically significant decrease by 10.4% from the baseline in the patients of group 1, while in groups 2 and 3 its changes were statistically insignificant. The lung compliance values in the patients of group 2 at this stage of the study were statistically significantly higher than in the patients of group 1. When comparing groups 2 and 3, no statistically significant differences were found.After surgery, lung compliance significantly decreased by 15.1% from the initial value in group 1. In the patients of groups 2 and 3, the decrease was insignificant and less than in group 1. It is important to underline that no statistically significant changes in this parameter were observed in the patients of groups 2 and 3 at all stages of the study.2/FiO2), a decrease in static lung compliance. The use of NO inhalation before and after CPB or NO inhalation during the entire operation (in combination with perfusion of the pulmonary artery and ventilation during CPB) made it possible to effectively maintain the values of lung compliance and pulmonary oxygenating function. There were no statistically significant changes in the parameters of lung compliance and PaO2/FiO2 depending on the type of NO inhalation (before and after CPB or during the entire operation). The use of the method of continuous NO inhalation during the operation (in combination with pulmonary artery perfusion and ventilation during CPB) statistically significantly reduced the growth of intrapulmonary shunting and alveolar-arterial difference after completion of CPB.Thus, our work demonstrated that with a standardized perioperative care protocol, after cardiopulmonary bypass, the pulmonary function parameters worsen, namely, an increase in the alveolar-arterial oxygen difference, an increase in intrapulmonary blood shunting, a decrease in blood oxygenation , two of them (6.6%) developed ARF. In the patients of group 2, the development of pulmonary dysfunction was observed in two patients (6.6%), one of them (3.3%) developed ARF. There was no development of postoperative pulmonary dysfunction among the patients in group 3.All the patients included in the study were discharged from the clinical departments of the hospital in a satisfactory state with clinical improvement in the underlying pathology after cardiac surgery under CPB. The diagnosis of pulmonary dysfunction in the early postoperative period was carried out on the basis of disturbances in lung mechanics (decrease in static lung compliance) and gas exchange disorders  after CPB. Gas exchange disorders were diagnosed on the basis of a decrease in the PaO2 criterion. A statistically significant earlier activation was demonstrated in the patients of group 3 compared to groups 1 and 2, the activation times being statistically significantly faster in the patients of group 2 compared with group 1. In the first 8 h after surgery, only 17 patients (56.6%) were activated in group 1, while in groups 2 and 3 — 22 (73.3%) and 26 (86.6%), respectively. There were no lethal outcomes in all three study groups.Comparative assessment of the time of respiratory support in the ICU in the three groups was carried out using the χ2 criterion) did not reveal a significant lower incidence of complications in the patients of group 3 compared with the others. At the same time, no statistically significant differences were found in the incidence of postoperative complications in the patients of group 2 compared to group 1. This indicator in group 1 was 16.6%, of which ACF developed in 6.6% of cases, ARF in 6.6%, and MODS in 3.3%. In group 2, complications developed in 10.0% of cases, equally in the number — 3.33% each. In the patients of group 3, the development of a postoperative complication (coagulopathic bleeding) was noted in only one case (3.3%), no connection was found between its development and the technologies used.Comparative assessment of the incidence of postoperative complications in the patients of all groups  through a ventilator before and after CPB; using the other technology (proposed by us), inhalation was performed throughout the entire operation, including the CPB time period, while during CPB, perfusion of the pulmonary artery and ventilation of the lungs were performed. With both technologies, the drug entered the blood by inhalation through the alveolar membrane of the lungs and it did not contact with the synthetic membrane of the oxygenator, the features of interaction with which have not yet been studied. Thus, the physiological inhalation way of the delivery of a gaseous agent is an indisputable benefit of the technology we use.The protective effect of NO inhalation on the heart is known to be associated with an increase in the amount of NO metabolites in the blood to the level sufficient to reduce ischemia-reperfusion injury to the myocardium . It is tThe results of our study of the pulmonary function parameters in the patients of the control group demonstrate a statistically significant increase in the alveolar-arterial oxygen difference, an increase in intrapulmonary shunting, and a decrease in oxygenation and lung compliance after cardiopulmonary bypass. The functional changes in the lungs in this group of patients presented in the study explain the appearance of pulmonary complications in the early postoperative period, namely the development of postoperative pulmonary dysfunction in 10.0% of the patients with the formation of acute respiratory failure in 6.6% of cases. Apparently, the development of postoperative pulmonary complications results from ischemiareperfusion lung injury. The received data on lung injury during CPB are consistent with the results of the previous studies –24.2 and lung compliance values during the entire operation, as well as a decrease in the incidence of early postoperative complications, which indicates the presence of a protective effect of this technology on the lungs. Apparently, here we should consider the effect of pharmacological preconditioning of lung tissue induced by NO inhalation [The patients of group 2 showed the preservation of the AaPOhalation –13.2, F-shunt, PaO2/FiO2, lung compliance) and the absence of early postoperative complications associated with pulmonary function.In the patients of group 3, when ventilation and blood delivery to the lungs are performed during the entire operation including the CPB time period, well-ventilated areas are constantly preserved in the lungs, which enables effective action of exogenous NO. Thereby, the intraoperative injury to the lung tissue is reduced. This is confirmed by high preservation of pulmonary function parameters (AaPOThis technology has been successfully implemented in clinical practice. A Russian patent was obtained for its development.The developed technology for the use of inhaled nitric oxide including its delivery during the entire operation with cardiopulmonary bypass together with pulmonary artery perfusion and ventilation of the lungs has a clinically marked protective effect on the heart and lungs.


A fatigue fracture has the characteristics of secondary crack, cleavage step, fatigue stripe, tire indentation, and dimple. The fracture is a mix of cleavage fracture and ductile fracture. Through a three-dimensional reconstruction of the alloy synchrotron radiation imaging area, it was found that the internal defects are small and mostly distributed at the edge of the sample. The dimple morphology is formed by cavity aggregation and cavity germination resulting from defects in the material itself, fracture of the second-phase particles, and separation of the second-phase particles from the matrix interface. By analyzing the damage mechanism of fatigue fractures, it is concluded that the cleavage step is formed by the intersection of cleavage planes formed by branch cracks, with the main crack of the confluence extending forward to form a cleavage fracture. The crack propagation path was also analyzed, and under the action of cyclic load and tip passivation, the crack shows Z-shaped propagation.In this study, using synchrotron radiation X-ray imaging, the microstructure, tensile properties, and fatigue properties of FGH96 nickel-based superalloy were tested, and the fatigue damage mechanism was analyzed. An analysis of the experimental results shows that the alloy structure is dense without voids or other defects. It was observed that the primary γ′ phase is distributed on the grain boundary in a chain shape, and the secondary γ′ phase is found inside the crystal grains. The X-ray diffraction (XRD) pattern indicates that no other phases were seen except for the γ and γ′ phases. The tensile strength of the alloy is 1570 MPa and the elongation is 12.1%. Using data fitting and calculation, it was found that the fatigue strength of the alloy under the condition of 5 × 10 The turbine disk is one of the most important components of the aero engine, and its working environment requires a high level of performance ,2. PowdeScholars at home and abroad have done much research on the fatigue properties of nickel-based superalloys. Hu et al.  studied The synchrotron radiation X-ray imaging technology of the Shanghai light source can obtain the three-dimensional structure of defects without destroying the material structure ,16. The In this paper, the size, shape, and distribution of the defects in FGH96 nickel-based superalloy are analyzed based on synchrotron radiation X-ray imaging. Testing the fatigue performance of the PM  FGH96 nickel-based superalloy turbine disk, determining the fatigue life limit of the material, and studying the fatigue damage behavior of the alloy have important basic theoretical significance for the development of new PM superalloy turbine disk materials and the safe operation of civil aircraft.The experimental material is the FGH96 nickel-based superalloy aviation turbine disk, which was provided by Aviation Industry Corp . The element content of the material is shown in The fatigue test dimensions were designed according to the national standard GB/t3075-2008, as shown in The internal defects of the material were detected at BL13W1 of Shanghai synchrotron radiation source see . The SR-23C6 [23C6  by the pAn XRD (X-ray diffraction) analysis of the surface structure of FGH96 nickel-based superalloy shows that it is mainly composed of γ and γ′. The phase composition is shown in The room temperature hardness of the FGH96 nickel-based superalloy sample was measured. To reduce the hardness measurement error and avoid accidental data, it was measured every 0.25 mm from the first point. A total of 20 points were tested, as shown in The tensile sample was tested. The relationship between material stress and strain is shown in According to the national standard GB/T15248-2008 “metallic materials axial constant-amplitude low-cycle fatigue test method”, the fatigue test was carried out using the lifting method, and the data in 6 cycles is 625.33 MPa by the linear fitting of The data in 3, there are 40 defects; for 50–200 μm3, there are six; and for more than 200 μm3, there are four. The sphericity of several larger defects in 3Al, which is an important strengthening phase of nickel-based superalloy.The fatigue test of the sample was continued, and the sample fractured when the cumulative number of cycles reached 5625. The fatigue fracture was imaged by synchrotron radiation X-ray. To analyze this phenomenon, due to the face-centered cubic structure of Ni-based superalloy with good slip properties, the cavities grow up gradually under cyclic loading and connect with other cavities to form dimple fractures, as shown in The cleavage plane and river pattern principle is shown in In the fracture morphology, many secondary cracks are found to expand as “Z”. A model was established, as shown in (1)The primary γ′ phase is distributed on the grain boundary in a chain shape, and the secondary γ′ phase is uniformly distributed inside the grain boundary. The average hardness of the alloy is 470.6 Hv, the tensile strength is 1570 MPa, and the elongation is 12.1%.(2)6 cycles, the fatigue strength of the alloy is 625.33 MPa, and the fatigue fracture is a mix of cleavage fracture and ductile fracture. In the crack growth zone, the secondary crack propagating along the tear ridge is the longest. Under the action of cyclic load and tip passivation, the crack propagates as a “Z” shape.Under the condition of 5 × 10(3)3 accounts for 80% of the total. The dimple morphology is formed by the growth and aggregation of cavities in the material. There are three cases of cavity germination: defects of the material itself, fracture of the second-phase particles, and separation of the interface between the second-phase particles and the matrix.Synchrotron radiation X-ray imaging shows that a defect volume less than 50 μm(4)Cleavage fracture is caused by the development of multiple cleavage planes formed by branch cracks that converge to form a main crack, the intersection of different cleavage planes to form cleavage steps, and the main crack continuing to expand forward until fracture. Cleavage fracture is the main factor in fatigue damage.(5)It is found that, compared with inclusions, voids are the main cause of fatigue fracture in FGH96 nickel-based superalloy. In future material manufacturing processes, while avoiding inclusions, the compactness of the material should be improved.


The animals were divided into two groups. The first group of animals (n = 7) was subjected to the perfusion procedure, and the second group of animals (n = 6) was not perfused. The brain tissues of the animals were homogenized, and the metabolite fraction was extracted with a water/methanol/chloroform solution. Samples were studied by high-frequency 1H-NMR spectroscopy with subsequent statistical data analysis. The group comparison was performed with the use of the Student’s test. We identified 36 metabolites in the brain tissue with the use of NMR spectroscopy. (3) For the major set of studied metabolites, no significant differences were found in the brain tissue metabolite concentrations in the native state and after the blood removal procedure. (4) Thus, it was shown that the presence of blood does not have a significant effect on the metabolomic profile of the brain in animals without pathologies.(1) Recently, metabolic profiling of the tissue in the native state or extracts of its metabolites has become increasingly important in the field of metabolomics. An important factor, in this case, is the presence of blood in a tissue sample, which can potentially lead to a change in the concentration of tissue metabolites and, as a result, distortion of experimental data and their interpretation. (2) In this paper, the metabolomic profiling based on NMR spectroscopy was performed to determine the effect of blood contained in the studied samples of brain tissue on their metabolomic profile. We used 13 male laboratory CD-1 In recent years, the number of applications of metabolomic tissue profiling for earlier diagnostics, monitoring the effectiveness of pathology therapy and assessments of the phenotype of living organisms has been rapidly increasing. One of the most powerful and versatile methods used in quantitative metabolomics studies is NMR spectroscopy ,2. The mAn important step in metabolomic studies is the choice of suitable biological samples. Urine and serum/plasma are widely used biofluids for studies. ,27,28,29Despite a variety of significant advances in the field of NMR technology, there are still several issues related to factors that can influence the results. One of the features of metabolomic profiling of tissues is the presence of blood in the tissue samples. In the case of in vitro NMR studies, the presence of blood can distort the metabolomic profile of the tissue. In the tissue studies of laboratory animals such as rats and mice, a perfusion procedure allows us to remove blood from the sample. However, when the study requires many samples, this procedure is laborious and time-consuming.Despite a large number of studies of tissues in the native state ,32, therThe method of preparation of biological samples using a three-component mixture of water/methanol/chloroform allowed for the extract purifying from proteins and lipids and minimizing the baseline distortion in NMR spectra ,35,36,37t-test for any of these metabolites. No multiple testing problem corrections, e.g., the Bonferroni correction, were applied.A typical NMR spectrum of the brain tissue of the CD-1 mouse line is shown in We reliably identified 36 metabolites and quantified the NMR spectra of extracts from the brain tissue of the CD-1 mice, which made it possible to make a comparison between the groups for the most abundant metabolites, which are often used for monitoring the pathological changes in biological and medical studies ,38,39.Deriving information on the metabolism of certain tissues may carry risks of sample contamination by other tissues and biological fluids of the organic body. Taking into account the structural and spatial organization of tissues may help us to avoid errors in the material intake, but separating all-penetrating biofluids from the tissues is often complicated. In this regard, a reasonable question arises about the potential contribution of biofluids to the errors in the analysis of the metabolism of tissue. In the metabolomic analysis by in vitro NMR, the vessels are involved in the volume of the sample taken, and can potentially lead to a significant error. In our work, we took the same sample volume  from both groups of animals, so in the group of animals after the perfusion procedure, the entire volume of the sample contained only brain tissue, and in the group of animals in the native state, the sample consisted of brain tissue mixed with blood. The volume of blood in the brain of a mouse averages 3.5–4.0% of the total brain volume. However, the percentage of blood varies for different areas of the brain. For the cerebral cortex, this parameter is equal to 7.9% . The res® IGS mice for this study. Initially, this line of mice was purchased from the Charles River Laboratories  in 2014. At the beginning of the experiment, the age of the animals was 8 weeks from the moment of birth. Mice were housed in open cages  in groups of 3 or 4 individuals of the same sex throughout the study. The animals were provided with food and water consumption ad libitum with a standard autoclaved food ssniff® R/MH autoclavable V1534-3 for rodents  and purified sterile water with the addition of “Severyanka” mineral salts . Conditions for keeping laboratory mice are also included: illumination—14 light: 10 dark, temperature 22–24 °C, and relative humidity 40–50%.The laboratory animals used in the experiment were born, reared, and throughout the study were kept in the “Center for Genetic Resources of Laboratory Animals” SPF-vivarium of the Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences (unique identifier RFMEFI62119X0023). We used 13 male laboratory CD-1n = 7) was subjected to the perfusion procedure (6 stages are described below). Group A: the second group of animals (n = 6), was not perfused. Group B: the sampling was limited to steps 1 and 6, but with the time for intake of material equal to group A.We divided the animals into two groups to collect the biomaterial for spectroscopy. The first group of animals (The procedure for mouse perfusing and sampling consisted of the following steps: (1) the animal was anesthetized intraperitoneally by injection of a domitor  and subsequent injection of zoletil ; (2) the animal’s chest was opened, exposing the heart; (3) a 5 mL syringe was filled with phosphate buffer pH 7.4  and attached to the catheter; (4) the needle of the catheter was inserted into the left ventricle of the mouse heart, the right atrium was cut with scissors; (5) 15 mL of PBS (approximately 10 times exceeding the volume of mouse blood) was injected for washing the circulatory system of the mouse. Perfusion was performed at the flow rate 5 mL/minute, so the procedure took 3 min. As was previously published, a required volume of PBS for transcardial perfusion of the mouse ranges from 10 mL up to 50 mL at a flow rate 5 mL/min or 7 mL/min respectively, which means that the whole perfusion procedure lasted from 2 to 7 min; ; (6) theAll experimental procedures were carried out in accordance with Directive 2010/63/EU of the European Parliament and the Council of the European Union of 22 September 2010 on the protection of animals used for scientific purposes, and approved by the Commission on Bioethics of the Institute of Cytology and Genetics SB RAS.v/v; 1600 µL of solvent mixture per 150 mg of wet tissue), vortexed for 30 s, kept on ice for 10 min, and incubated at −20 °C for 20 min. The mixtures were centrifuged at 12,000 rpm, 4 °C for 30 min to pellet proteins. The top hydrophilic fraction was collected into fresh vials and lyophilized using a vacuum concentrator.To obtain a protein-free extract of metabolites from the mouse brain, we used the following sample preparation protocol. Brain tissue was weighed and homogenized using a TissueRuptor II homogenizer  in a cold water/methanol/chloroform mixture in a ratio 1:2:2  containing 6 × 10−6 M DSS  as an internal standard and 20 mM deuterated phosphate buffer to maintain pH 7.4. The 1H-NMR measurements were carried out with the use of an NMR spectrometer AVANCE III HD 700 MHz  equipped with a 16.44 T Ascend cryomagnet. The proton NMR spectra for each sample were obtained with 96 accumulations. The temperature of the sample during the data acquisition was kept at 25 °C, the detection pulse was 90 degrees. The repetition time Tr between scans was 25 s to allow for the relaxation of all spins. The relaxation times T1 for some compounds are given in 1 (for the majority of spins) or, at least Tr > 3T1 (for spins with longest relation times such as histidine) is fulfilled. Low power radiation at the water resonance frequency was applied prior to acquisition to presaturate the water signal. The pulse sequence zgpr was applied. The baseline correction and integration were done manually using the free demo version of the program MestReNova v12.0.Dried extracts were re-dissolved in 600 µL of DIn a typical NMR spectrum of a blood serum extract, one can identify approximately 50–70 compounds ; however, some of the signals are weak or partly overlapped by other signals; that can cause significant experimental errors in the integration of these signals. For this reason, only 36 metabolites giving strong and distinct signals in NMR spectra were chosen for the analysis. The attribution of signals which have been used for the metabolite quantification in the NMR spectrum is shown in −6 M was added to each sample. When identifying metabolites, the NMR signals were assigned to specific functional groups of molecules, which made it possible to determine the number of protons that contributed to each signal of the metabolite. The integral values were normalized to the number of protons corresponding to the integrated functional group. Since many metabolites have several NMR signals in different regions of the spectrum, the distinct signals with minimal overlapping by other signals were taken for the concentration determination  of a tissue used for the sample preparation.The signal assignment was performed using the human metabolome database  and our tion see . The con1H NMR spectroscopy allowed us to reliably identify and quantify 36 different metabolites. Analysis of brain tissue metabolite concentrations in the native state and after the blood removal procedure showed that the presence of blood does not have a significant effect on the metabolomic profile of the brain in animals without pathologies. Based on the data obtained, it can be concluded that the metabolomic analysis of animal brain tissue does not require a laborious procedure for removing blood from the studied samples. At the same time, this is only valid for situations without significant changes in the blood metabolome; in the presence of such changes, additional studies are required.In the course of this work, we studied the brain tissue of CD-1 mice to assess the effect of blood on the metabolomic profile of a tissue sample in its native state. The method of high-field


Compared with previously proposed YBAR with suspended structure, the proposed SM-YBAR can effectively suppress unwanted spurious modes with only a slight loss of the electromechanical coupling coefficient. The SM-YABR also provides better device stability, possible low-temperature drift coefficient, and a more convenient and mature device processing. It has the potential to meet the multiple requirements for the next generation signal processing devices in terms of high frequency, large bandwidth, stability, and low cost, etc.This paper proposed a solid-mounted (SM) longitudinally excited shear wave resonator . By adopting a 200 nm x-cut LiNbO Microwave acoustic devices based on surface acoustic waves (SAW) and bulk acoustic waves (BAW) are of great value in the communication and sensing fields. The core of these devices is the microwave acoustic resonator, which can further construct today’s mainstream microwave acoustic filters, duplexers, multiplexers, and various kinds of sensors ,2,3,4. W3) films, thanks to their ability to simultaneously meet high working frequency, large electromechanical coupling coefficient, and high Q at the same time [3 film. It can achieve an electromechanical coupling coefficient of more than 25% while having a working frequency over 4 GHz, further realizing a high-quality filter with a bandwidth up to hundreds of MHz [Bulk acoustic resonators (BARs) based on single-crystal lithium niobate  and interdigital electrodes (IDTs) on its top surface, while the YBAR has one more electrode at the bottom of the piezoelectric film than the XBAR. Similar to the XBAR, the YBAR was proposed in 2020 , in whicIn principle, for BARs based on piezoelectric films, including the XBAR and YBAR, there are two methods to suppress the radiation of the BAW from the film piezoelectric to the substrate. One is to suspend the piezoelectric film , and the other is the acoustic Bragg reflector ,15. The 3 film with excellent performance. In the simulation of 3D finite element analysis (FEA) software COMSOL Multiphysics, by adopting a 200 nm x-cut LiNbO3 film (available in the current industry), the SM-YBAR achieved a resonant frequency of over 5 GHz and a large electromechanical coupling coefficient of more than 50%. 3. Moreover, devices with non-suspended structures have better mechanical stability than those that are suspended, so the SM-YABR is more suitable to meet the application requirements of various mobile scenarios in the new generation wireless communications. Below, we will discuss specifically the SM-YBAR in its design principle, material selection, and geometrical configuration with corresponding numerical calculations/simulations.In this paper, we studied and proposed a solidly mounted longitudinally excited shear wave resonator (SM-YBAR) based on x-cut LiNbO3 [3-based BAWRs (including the YABR), the x-cut LiNbO3 has a higher piezoelectric coefficient than other crystal cuts [3 film to ensure that the YBAR has a larger electromechanical coupling coefficient.Due to the anisotropy of the single LiNbO3 , differetal cuts . Consequ3 film that determines the piezoelectric coefficient but also the direction along which the IDTs are placed on the top surface of the LiNbO3 film. In this paper, we denoted the placement direction of IDTs as the vertical direction of their electrodes, as shown in 3 film, as shown in ije is the piezoelectric coefficient, which is the main factor determining 2K, iiε is the relative permittivity, and jjc is the elastic modulus. In e34, while mode2 and mode3 are both spurious modes with corresponding piezoelectric coefficients e16 and e35, respectively. The electromechanical coupling coefficient reaches its maximum when the IDTs are placed in the direction of 30°-y, while some other spurious modes are relatively weak. Therefore, in this paper, we chose to place IDTs on the x-cut LiNbO3 surface along the 30°-y direction.Specifically, for the YABR, it is not only the crystal cut of LiNbO3 film, the main factor determining the resonance frequency of the YBAR is the thickness of the LiNbO3 film but not the period of IDTs. At the same time, the metal electrode layers above and below the LiNbO3 film will also have an impact on the longitudinally excited shear wave. In order to reduce this effect, the thickness of the metal electrode should be reduced as much as possible. As the calculation results show in 3 film thickness. When the film thickness is 200 nm, the resonance frequency is over 8 GHz. Considering the influence of metal electrodes , the resonance frequency of the YBAR will be lower, but still higher than 4 GHz. We also studied the influence of the LiNbO3 film’s thickness on the electromechanical coupling coefficient. When the LiNbO3 film is thinned to a certain thickness (around 200~300 nm), the electromechanical coupling coefficient will rapidly decrease as the film thickness decreases. When the LiNbO3 film thickness is 200 nm, using Pt as the bottom electrode will have a larger electromechanical coupling coefficient but a lower resonance frequency than using Al, and will have a larger electromechanical coupling coefficient and a higher resonance frequency than using Au. Hence, in the research later in this paper, we chose to adopt 50 nm Al and Pt as the top and bottom electrodes of the resonator based on 200 nm x-cut LiNbO3. In this choice, the YBAR would get a resonance frequency over 5 GHz and an electromechanical coupling coefficient over 60%. However, it should be noted that an Al bottom electrode is also an advantageous choice.In the YBAR, since the excited shear wave will propagate perpendicular to the piezoelectric LiNbO3 film is set to 200 nm; the thickness of the aluminum (Al) IDTs on the top surface of the LiNbO3 film is 50 nm, with identical electrode width of 0.5 μm and a period of 2 μm; the thickness of the platinum (Pt) electrode at the bottom of the LiNbO3 film is 50 nm.In this section, we numerically studied the performance of four kinds of YBARs  in different structures by the finite element method (FEM), using the piezoelectric module of commercial software COMSOL Multiphysics. As shown in 2O3) substrate. In device B, there is only the Al2O3 substrate supporting the (from the top surface to the bottom) Al-LiNbO3-Pt layer. In device C, there is an alternately arranged SiO2-Al2O3 multilayer  added between the Al-LiNbO3-Pt layer and the Al2O3 substrate. The structure of device D is similar to that of device C, while the multilayer is made of SiO2 and Pt . These two kinds of alternately arranged multilayers play the role of Bragg reflectors in the BAWR, reducing the BAW radiation from the LiNbO3 film to the Al2O3 substrate.Device A is a YBAR with a suspended structure. Devices B, C, and D are SM-YBARs, all on a sapphire , the Bragg reflector will have the best working ability for acoustic wave reflection [2, and Al2O3 layers as 0.060 μm, 0.174 μm, and 0.295 μm, respectively.In the Bragg reflectors, the Pt layers and the Alflection . Under t3 film refer to the literature [2 and Al2O3 films refer to the literature [In our simulations, the material parameters  setting of the single crystal LiNbOterature ,6, and tterature ,21. In asf is the peak value of the admittance map, and pf is the valley value. It can be seen that, except for device B, the other three devices can achieve good BAW resonance effects, and their electromechanical coupling coefficients are all over 50% .Calculated BAW field displacements and admittance of the four devices are also shown in pf. Examining the BAW field displacements of these spurious modes (shown in the insets), we found that the appearance of these spurious modes is closely related to the free-boundary bottom Pt electrode of the device. In devices C and D, since the bottom Pt electrode no longer serves as a free boundary, but is sandwiched solidly between the LiNbO3 film and the substrate, these spurious modes are effectively suppressed.Comparing the results of device A and devices C/D, the former has obvious spurious modes near Comparing the results of devices C and D, we found that the Bragg reflectors of different materials have little inference on resonance frequency and electromechanical coupling coefficient of the YBAR. Therefore, the materials used for the BAW Bragg reflector can be selected in various ways according to the practical device processing, the needed temperature drift of the device, and other considerations.According to the design of device D in the previous section, we also performed a full 3D simulation of the SM-YBAR. In this simulation, both the aperture of the IDTs (set to 36 μm) and their busbar electrode are considered. 4. In practical terms, limited by the finite size of the device and all of its losses, the Q value will be lower than the simulation result. Compared with the result of the SM-YBAR obtained by the simulation in the previous section, the electromechanical coupling coefficient of the device obtained by the 3D simulation is still over 50%. There are some peaks of spurious modes in the admittance spectrum, but they are negligible compared with the main peak , thus, hardly affecting the performance of the device.It can be seen that the BAW at resonance is mainly concentrated in the IDTs area. This is conducive to achieving a high-quality factor (Q) of the resonator. In this paper, the simulated SM-YBAR has a theoretical Q reaching 103 film, (2) thickness of the LiNbO3 film, (3) thickness and materials of the top and bottom electrodes, and (4) thickness and materials of the multilayers Bragg reflector. After these, since the SM-YABR has a relatively simple structure, there is not much room for further design, except the period and electrode-width of the IDTs. Although the electrode period does not directly determine the operating frequency of the YABR, as in SAW devices, a reasonable period helps suppress the spurious mode in the YABR. After research, it was found that when a quarter period of the IDTs was similar to the equivalent wavelength of the BAW at its working frequency, i.e., a 2 μm period of IDTs at the working frequency around 5 GHz, all spurious modes in the working bandwidth were near-perfectly suppressed, as the calculated results in Above, we have clarified the design of the SM-YBAR in the following aspects: (1) crystal cut and orientation of the LiNbO3 single crystal film on the multilayer substrate can be prepared by the smart-cut technology used in many advancing BAWRs. This proposed process avoids the direct bonding of the LiNbO3 film to the bottom electrode. Instead, the bottom electrode is produced by depositing on the surface of the He+ implanted LiNbO3.For our SM-YBAR, we propose a possible manufacturing process, as shown in 3 film, (2) thickness of the top and bottom electrodes, (3) thickness of the multilayers in the Bragg reflector and (4) electrode-width of the IDTs.Due to errors in the actual manufacturing process, the actual geometric dimensions of each part of the device will inevitably deviate from the designed size to a certain extent. The geometric parameters that may deviate mainly include (1) thickness of the LiNbOWe have investigated the device performance after these geometric parameters deviate from the design value, and the results are shown in 3 film. Based on 3D simulations using the finite element method, by adopting a 200 nm LiNbO3 film and electrodes width of 500 nm, the SM-YBAR offers a resonance frequency exceeding 5 GHz and an electromechanical coupling coefficient exceeding 50%. Compared with the previous YBAR with a suspended structure, an SM-YABR naturally has a better stability. Additionally, its processing is more convenient for avoiding the etching of LiNbO3, which is still a challenge in the industry today. Even advantageously, an SM-YBAR effectively avoids the spurious modes that are prone to appear in the suspended YABR. With the rapid development of LiNbO3 thin-film technologies, we believe that the proposed SM-YBAR is promising for advancing high-throughput radio frequency devices in mobile communications.For the realization of a microwave acoustic resonator with high frequency (greater than 5 GHz), large electromechanical coupling coefficient (larger than 50%), high device stability, and simple preparation processing, this paper proposed a solid mounted longitudinally excited shear wave resonator  on an x-cut LiNbO


In order to improve the mechanical properties of asphalt pavement, geosynthetics can be employed in asphalt mixture. This research designed 12 reinforced schemes based on the types of geosynthetics, bonding layers and reinforced position. For the relative tests carried out, reinforced specimens were prepared according to each individual scheme. Moreover, rutting tests, bending creep tests and split fatigue tests were carried out on reinforced specimens in the laboratory. The results obtained in this investigation showed that the dynamic stability, bending creep rate and fatigue life of geocell-reinforced specimens are better than those of geogrid-reinforced specimens. The bonding layer of Styrene-Butadiene-Styrene (SBS) modified asphalt is better than epoxy modified asphalt. The dynamic stability and fatigue life of middle reinforcement are better than those of the lower reinforcement, while the bending creep rate of the lower reinforcement is better than middle reinforcement. In addition, reinforced scheme (9) has the largest increase in dynamic stability and fatigue life by 103 and 137%, respectively, and reinforced scheme (12) has the largest reduction in bending creep rate by 46%. However, scheme (9) improved dynamic stability and fatigue life by 43 and 29% higher than scheme (12), while the reduction of flexural creep rate of scheme (12) is only 7% higher than that of scheme (9). Currently, asphalt pavements are subjected to high traffic volumes generating distresses such as rutting and cracking that need frequent and expensive maintenance ,2. In geAs a common pavement distress, rutting will reduce the quality of pavement service and cause safety hazards. Bertuliene et al.  conducteWhen the base layer produces shrinkage cracks or low-temperature shrinkage cracks, the contact position between the bottom of the asphalt layer and the crack is prone to stress concentration under the action of the vehicle, causing the asphalt surface to form a reflective crack. An experimental program was conducted to determine the effects of geosynthetic reinforcement on mitigating reflection cracking in asphalt overlays by Khodaii et al. ; resultsIn addition to rutting and reflection cracks, fatigue cracks are also one of the main manifestations of asphalt pavement distress. Dawei et al.  applied Although the use of geosynthetics for reinforcement of asphalt pavement has been verified by most researchers in various aspects ,22,23, tGiven this background, the research presented in this paper aims to evaluate the effectiveness of asphalt mixture reinforcement with different reinforced schemes. To this purpose, rutting tests, bending creep tests and split fatigue tests were carried out on reinforced specimens in the laboratory. Two reinforcing materials, three bonding layers and two reinforced positions were considered for the realization of the laboratory specimens. Unreinforced reference systems were also included for comparison purposes.The aggregate used for the specimen was basalt , and the binder was SBS-modified asphalt  which has been widely used in China. Considering the smaller grid size of geosynthetics in laboratory tests, the dense-graded AC-13 with a smaller particle size was selected for the gradation, as shown in 2 of residual bitumen was spread at the interface.During the experimental investigation, two different types of grid coatings were applied at the interface of the geosynthetics: an SBS polymer modified asphalt and an epoxy modified asphalt . Among them, epoxy modified asphalt is an irreversible cured product formed by adding epoxy resin to asphalt, and hardening reaction with curing agent. The main technical indicators are shown in The geocell used for this study consists in a Polypropylene  material that is known for its high strength and temperature resistance. As for the other reinforcing material geogrid, it is made of high-strength glass fiber  through the international advanced warp knitting process. The properties of PP geocell and GF geogrid  given byAccording to the types of geosynthetics, bonding layers and reinforced position, 12 different reinforced schemes are finally designed as shown in Comparing (1) with the other 12 types of reinforced structures, we can see the effect of reinforcement under each of the above-mentioned reinforcement conditions. By comparing (2), (3), (4), (5), (6), (7) and (8), (9), (10), (11), (12), (13), the difference between geogrids and geocells under different reinforcement conditions can be obtained. By comparing (5), (6), (7), (11), (12), (13) and (2), (3), (4), (8), (9), (10), we can get the influence of the position of reinforcement under different reinforcement conditions. By comparing (2), (5), (8), (11), and (3), (6), (9), (12), and (4), (7), (10), (13), we can know the role of the bonding layer in the process of reinforcement under different reinforcement conditions.At present, there is no standard specimen of geosynthetic-reinforced asphalt mixture, so this study refers to the standard specimen of asphalt mixture. The specimens of rut board were formed by wheel grinding and its size was 0.3 m × 0.3 m × 0.05 m, as shown in In this study, the comparison between the results obtained from mechanical tests performed on geosynthetic-reinforced and unreinforced specimens was carried out to evaluate the performance of different reinforced schemes. The placement of geosynthetics in the asphalt layer mainly aims at three pavement distresses, which are cumulative permanent deformation of the pavement (rutting), bottom-up reflective cracks, and fatigue cracks under cyclic loading. Therefore, the above-mentioned 12 reinforced schemes were used to conduct rutting test, fatigue test, and bending creep test, and the whole experimental program is summarized in Before the rutting test, the specimens were placed in the environmental chamber and cured for 6 h at the target temperature. The wheel pressure during rutting test was 0.7 MPa, which was the same as that under standard axle load. The loading device for rutting tests is shown in According to the research results ,27, the In the split fatigue tests, the fixture strip of the standard specimen is arc-shaped. In order to prevent stress concentration when the two ends of the strip are in contact with the surface of cube specimen, a self-made long strip with a flat surface is used. The fatigue load is a stress-controlled haversine and no intermittent time is set to accelerate the fatigue process. Before fatigue tests, the specimens were also cured at the target temperature for 6 h, and the loading device is shown in In the above-mentioned tests, discard the difference according to the degree of dispersion of the test results, and supplement the test to ensure that the effective test is not less than three times.The vertical permanent deformation accumulated in asphalt pavement is the main cause of rutting. Rutting will seriously affect the comfort and safety of pavement and shorten its service life. The relationship between the number of loading cycle and the accumulate vertical deformation under the scheme in rutting test is shown in DS) under different reinforcement schemes was calculated, and the calculation method is shown in Equation (1).The dynamic stability .σ0 is the creep bending stress, iε is the bending strain at the bottom of the beam, b and h are the width and height across the interrupt plane, respectively, L is the span, L1 is the distance from the end to the fulcrum, q is the mass per unit length, calculated by the following formula: q = (D − 1) × b × h × 1000 × 9.81, D is the density of asphalt mixture, F0 is the creep load, id is the mid-span deflection, and sε is the bending creep rate (1/(s·MPa)).In the above formula, σ0 and the constant coefficient α are shown in According to the physical and geometric characteristics of the beam specimens, the values of the various parameters in the above formula as well as the calculation results of the flexural stress The above method was used to read the starting and ending positions of each reinforcement scheme in the stable period, and the bending creep rate was calculated according to Equation (2). The results are shown in t1 and t2 in From Fatigue crack is one of the main failure forms of asphalt pavement, and it is the process of initiation, propagation, and penetration of micro-cracks in asphalt mixture. The frequency and amplitude of the loading curve need to be determined before conducting the split fatigue test. According to the experimental program, the frequency is 10 Hz, and the loading amplitude is 30% of the splitting strength of the unreinforced specimens. The ultimate splitting load is 24 kN, so the loading amplitude is 7.2 kN. The cumulative strain of the split fatigue test under the above reinforcement scheme is shown in As can be seen from As can be seen from The data monitored during the rutting test is the cumulative vertical permanent deformation under different cycles, the data monitored in the bending creep test is the vertical displacement of the beam center with time under constant load, and the monitoring data in the splitting fatigue test is the accumulated strain under cyclic loading. Taking the unreinforced as a benchmark, the calculation method of the percentage change of each index after reinforcement is unified as shown in Equation (3).RI is the index when reinforced, UI is the index when unreinforced, and IC is the percentage change of the index.In the formula, According to It can be seen from The results obtained during this experimental investigation, carried out in order to study the performance of geosynthetics for asphalt pavement applications, allow several conclusive remarks to be made concerning rutting tests, bending creep tests and split fatigue tests.(1)Geosynthetic reinforcement can restrain the vertical permanent deformation of asphalt mixture under the circulation wheel in rutting tests and improve the dynamic stability, extend the bending creep process of asphalt mixture under the constant load in bending creep tests, reduce the bending creep rate, decrease the cumulative strain of asphalt mixture under the cyclic load in fatigue tests, and improve the fatigue life.(2)From the perspective of the types of geosynthetics, the reinforcement effect of geocells is much higher than that of geogrids. From the perspective of bonding layers, the reinforcement effect of SBS modified asphalt bonding layer is slightly better than that of epoxy modified asphalt bonding layer and both are better than that of no bonding layer. From the perspective of reinforced position, the rutting and fatigue resistance of middle reinforcement are better than that of the lower reinforcement, and the crack resistance of lower reinforcement is better than that of the middle reinforcement.(3)According to the dynamic stability, bending creep rate and fatigue life, it can be seen that the reinforcement scheme (9) has the largest increase in dynamic stability and fatigue life, which are 103 and 137%, respectively. The reinforcement scheme (12) has the largest reduction in bending creep rate, reaching 46%. The improvement of dynamic stability and fatigue life of scheme (9) is 43 and 29% higher than that of scheme (12), while the reduction of bending creep rate of scheme (12) is only 7% higher than that of scheme (9).