There is slight evidence on the effectiveness of relaxation techniques to improve quality of life of the old people, and no comparative studies have particularly investigated this population. Hence, the present study was conducted to examine the effect of Mitchell relaxation versus Benson relaxation technique to improve quality of life of the old people.In the present quasi-experimental study, 96 eligible old people in a nursing home were selected by available sampling method. Afterwards, they were assigned to three groups: Mitchell’s Relaxation Technique, Benson Relaxation Technique, and control (each of 32 participants) using the random block sampling method. The intervention groups received relaxation for 8 weeks and 3 sessions of 20 min each week. However, the control group did not receive any relaxation. Data was gathered by questionnaires (SF-36) and (CASP-19) before (week 0) and after the intervention (week 8) and were analyzed using the SPSS software version 26.The results indicated that both Benson and Mitchell relaxation had improved the quality of life (SF-36) and (CASP-19) and their sub-scales in the participants compare to the control group (P < 0.001). Accordingly, the median  of the specific quality of life of the participants before the intervention was 21  in the Benson group, 20.5  in the Michel group, and 21  in the control group. However, after the intervention they reached 35, 34.5, and 17  respectively. There was no statistically significant difference between the Benson and Michel relaxation groups.Based on the results, Benson and Mitchell relaxation techniques improve the quality of life of the old people. If the results be confirmed in other studies, the education of each of them, especially for the old people living in nursing homes and their caregivers, is suggested as routine care.The online version contains supplementary material available at 10.1186/s12877-023-04378-z. According to the definition of the World Health Organization, people over 65 years old are considered old people . AccordiAccording to numerous studies, older individuals living in nursing homes have a lower quality of life than his/her peer who lives at home. Therefore, in addition to achieving a good quality of care , nursingIn order to improve the QOL of the old people, various interventions and health care, including health interventions, interdisciplinary interventions and sports interventions, have been used which have had different outcomes . ConsistMitchell’s Relaxation Technique (MRT) is another relaxation technique. The basis of this method is mutual inhibition of muscles and diaphragmatic breathing as well; i.e., when a muscle is involved, the muscles of the opposite group are in a state of relaxation . MRT is In a study, Biabani et al. found Jacobson method to be more effective than BRT on elderly depression . In a stIsolation problems, lack of family support and presence with the old people, disability, physical and psychological problems such as depression, stress and anxiety have reduced the QOL of the old people living in nursing homes. On the other hand, the side effects of drugs in old age and the limitation of physical activity of the old people make it necessary to investigate the effect of palliative care, including Benson and Michel’s relaxation techniques, and to find the best technique for improving their quality of life. Therefore, the present study was conducted with the aim of comparing the effects of Benson’s Relaxation Technique and Mitchell’s Relaxation Technique on the quality of life of the old people living in nursing homes. Moreover, this question is raised that which of these two relaxation methods has a greater effect on the quality of life of the residents of nursing homes?The present research was a quasi-experimental controlled study with a pre-test post-test design. The interventions included both Benson and Mitchell the relaxation techniques, and the outcome variable was the quality of life of the old people, which was measured before (week 0) and after the intervention (week 8).The study population included the old people residents of Khwaja Nasir al-Din Toosi Nursing Home in Maragheh, Mohabbate in Tabriz and Alavi Azarshahr in East Azarbaijan Province, Iran. The research location was Khwaja Nasir al-Din Tousi’s nursing home Mohabbate and Alavi, which are respectively located in the cities of Maragheh, Azarshahr and Tabriz in East Azarbaijan Province, Iran.The number of samples was based on the parameters α = 0.05, α-1=/95, Β = 0.2, β=-0.85, Z1 -α/2 = 1.96 and Z1 -β = 85/85. Moreover, the standard deviation of the quality of life was equal to µ1 = 5.1, 1.34 and µ2 = 30.2, 14, the number of people in each group was 26. However, taking into account 20% attrition, a total number of 32 people in each group and a total of 96 people were considered [Eligible participants were selected by available sampling method and were assigned to 3 groups of MRT (32 people), BRT (32 people) and control group (32 people) using random block sampling method.First, by calculating the number of study groups (two intervention groups and one control group), the number of people in each block was equal to 3, and then using the factorial law (3! =1 × 2 × 3 = 6) the number of 6 blocks were calculated. The randomization and selection of blocks continued until 32 elder individuals were placed in the Benson relaxation intervention group, 32 older persons were placed in the Mitchell relaxation intervention group, and 32 older individuals were placed in the control group.Inclusion criteria included: ability to communicate and answer questionnaire questions, age over 65 years old, living in a nursing home, obtaining a lower-than-average QOL score (28–78) and cooperating with the researcher to carry out interventions. Exclusion criteria were mental or cognitive impairment in according to medical records, and physical disability. In addition, those who did not meet the inclusion criteria were excluded from the study.The data were gathered by two structured and self-reported questionnaires, including the 36-Item Short Form Survey of quality of life (SF-36 QOL) and the special questionnaire for measuring the quality of life of the old people including constructs of ‘control’, ‘autonomy’, ‘self-realization’, and ‘pleasure’ (CASP-19 QOL).SF-36 QOL was developed by Ware and Sherbourne . This quThe CASP-19 QOL was designed in England. It includes 19 specific items that consist of 4 subscales of control (4 items), autonomy (5 items), self-realization (5 items), and pleasure (5 items). The scales of this questionnaire are Likert ratings, which have four options: “most of the time”, “sometimes”, “not often” to “never”. The lowest score for each statement is “zero” and the highest “score” is “three”. The scoring of the 6 statements of the questionnaire includes items 8, 6, 4, 2, 1, and 9 were scored in a reverse form .This questionnaire has been translated into different languages. In Iran, Heravi et al. confirmed its validity and reliability in the Iranian society in 2014. The maximum score of the questionnaire is 57  and the lowest is zero  , 25.Considering that Some of the participants were illiterate and to avoid bias, the questionnaires were completed by structured interview with all the participants by a colleague at the beginning of the study (week 0) and at the end of the interventions (week 8).All sessions of Mitchell relaxation intervention were completed by the participants for 8 weeks and every week during 3 sessions of 20 min  under the guidance of two researchers  according to the relaxation protocol Mitchell .The Benson relaxation intervention was completed by the elder individual for 8 weeks and every week during 3 sessions of 20 min  under the guidance of the researcher  in a room in order to respect the privacy of the participant according to Mitchell relaxation protocol , 27.The intervention for each participant was done separately in a room at the nursing home respecting the privacy of the patient under supervision and guidance of the researcher. All intervention sessions at Khwaja Nasir al-Din Toosi Nursing Home in Maragheh were conducted on even days and in Alavi Nursing Home in Azarshahr in East Azarbaijan Province, and Mohabbate in Tabriz in Iran on odd days from 8:00 am to 16:00 pm under the supervision and guidance of the researcher and a colleague  and were implemented by the participants. In order to avoid bias in each nursing home, based on the fixed list of participants, odd numbers were assigned to the researcher and even numbers assigned to the colleague, and vice versa for the next session.The control group did not receive any relaxation technique.Data were analyzed using the SPSS software (version 26) with a significance level of P < 0.05. One-way analysis of variance test was used for the age variable, and chi-square test was used for other demographic information. The data distribution was checked using the Kolmogorov-Smirnov test, the results indicated that they do not have a normal distribution. Therefore, Kruskal-Wallis tests were used for between-group comparisons, Bonferroni post hoc tests for pairwise comparisons, and Wilcoxon tests for intra-group comparisons.In the present study, 96 participants remained until the end of the study Fig. . The aveBefore the research intervention, no statistically significant difference was observed in the distribution of the QOL (CASP-19 questionnaires), and the QOL SF36) of the participants and their subscales, between the intervention and control groups. After the intervention, however, a statistically significant improvement was observed in the distribution of the QOL (CASP-19 questionnaires) and the QOL (SF36) of the participants and their subscales, between the intervention and control groups (P < 0.05) Tables  and 3.6 of the In a pairwise comparison, a significant difference was displayed in the distribution of the QOL (CASP-19 questionnaires), and the QOL (SF36) of the participants and their subscales between each of the Benson and Mitchell intervention groups compared to the control group (p < 0.0001). On the other hand, no statistically significant difference was observed in the distribution of both QOL scores and their subscales between the Benson and Mitchell relaxation groups.The distribution of all subscales of the QOL (CASP-19 questionnaires), and their subscales in the Benson and Mitchell relaxation intervention groups indicated a significant improvement after the intervention compared to beforehand (p < 0.05). In the control group, there were a significant decrease in the distribution of the QOL (CASP-19 questionnaires) of the participants (p = 0.001) and its autonomy dimension (p = 0.037) after the research intervention compared to before. Table .The results indicated that the distribution of quality of life (SF36) and its subscales of the participants in the two intervention groups of Benson and Mitchell intervention compared to before the intervention indicated a statistically significant improvement (p < 0.05). On the other hand, in the control group, only the vitality subscale distribution exposed a significant decrease after the research intervention compared to before the intervention. Table .The present study compared the effect of BRT and MRT on the QOL of the elderly residents of nursing homes. To date, no study parallel to the present study has been conducted. The results of the present study indicated that the implementation of MRT and BRT in the intervention groups had improved the QOL (CASP-19), its subscales, the QOL (SF-36) and its subscales  of the participants. On the other hand, both BRT and MRT had improved quality of life scores (SF-36) and specific quality of life of the participants and their subscales.In the present study, the Benson relaxation intervention improved the QOL (CASP-19) and QoL (SF-36) and most of their subscales. Similar to the results of the present study, in the study by Habibollahpour et al., it was revealed that the quality of sleep of the old people using Benson’s relaxation method had improved . In the In line with the findings of the present study, the results of a systematic review by Pangaribuan et al. exhibited that the BRT reduced depression, stress, and anxiety in hemodialysis patients and improved their quality of life and mental health . In the In the present study, Mitchell relaxation intervention improved the QOL (CASP-19) of the participants and the QOL (SF-36) and its subscales. Similar to the results of the present study, Amirova et al., indicated that the Mitchell relaxation intervention was effective in reducing pain, fatigue, and sleep problems and improved the QOL of the patients with fibromyalgia . RelaxatThe results of the present study indicated that both Mitchell and Benson relaxation techniques improved the QOL of the participants. A study comparing the effect of Benson and Mitchell relaxation techniques was not found, but there were comparisons between each of these methods with other relaxation techniques. In a research by Moradi et al., Jacobson’s technique was more effective than Benson’s on depression in the older individual . This suContrary to the results of the present study, a study by Hoseinian et al., Jacobsen’s relaxation technique using a mobile application did not improve the anxiety and occupational stress of nurses caring for patients with Covid-19 . HoweverIn the present study, the independence dimension of the QOL (CASP-19) in the control group declined after the research intervention, which was expected from the old people residing at nursing homes. The researcher’s control over the environment and time of the research, supervision and assistance of the researcher in carrying out interventions by the old people and no exclusion of participants in the research period were among the strengths of the present research.The limitations of the present study were the lack of follow-up time after the intervention and the completion of two QOL questionnaires with many questions, which due to the age and complications of the old people individuals may have bored them that may have led them to answer the questions with less care.Based on the results of the present study, it can be assumed that the use of each of the Benson and Mitchell relaxation techniques improved the QOL of the old people. Therefore, the instruction of each of the two relaxation methods is suggested as effective, comfortable and low-cost methods for the older individuals, especially the old people living in nursing homes and their caregivers as routine care.In addition, the use of both the specific quality of life (CASP-19) and the quality of life (SF-36) questionnaires have displayed similar results. Therefore, only one questionnaire, preferably a specific quality of life questionnaire, should be used to measure the quality of life of the old people.It is suggested that the effect of relaxation interventions on the quality of life be investigated in a follow-up period of 3 to 6 months.Below is the link to the electronic supplementary material.Supplementary Material 1


The incorporation of polycarboxylate ether superplasticizer (PCE)-type polymers and silica fume (SF) in high-performance concretes (HPC) leads to remarkable rheological and mechanical improvements. In the fresh state, PCEs are adsorbed on cement particles and dispersants, promoting the workability of the concrete. Silica fume enables very well-compacted concrete to be obtained, which is characterized by high mechanical parameters in its hardened state. Some PCEs are incompatible with silica fume, which can result in slump loss and poor rheological behavior. The main objective of this research is to study the influence of three types of PCEs, which all have different molecular architectures, on the rheological and mechanical behavior of high-performance concretes containing 10% SF as a partial replacement of cement. The results show that the carboxylic density of PCE has an influence on its compatibility with SF. According to the World Cement Association (WCA), the cement industry is responsible for 5–6% of global carbon dioxide emissions . This as3Al(OH)6 12H2O]2(SO4)3 2H2O [PCEs are currently the most effective at reducing the water content (up to 40%) and improving the workability and fluidity of concrete compared to other types of superplasticizers. PCEs are copolymers and have a comb structure ,9. The m4)3 2H2O . This oc4)3 2H2O ,19,20,214)3 2H2O ,23,24,25The adsorption and dispersing capacity of PCEs in cement-based materials depends on their chemical structure as well as their molecular weight, carboxylic groups, density, and length of the side chain ,27,28. STo the best of our knowledge, the effectiveness of PCEs in high-performance concrete (HPC) containing silica fume (SF) as a partial replacement of cement has not been fully investigated. There are several knowledge gaps regarding this matter, especially concerning the interaction of SF and PCE (with different molecular weights and carboxyl densities) in HPC. To fill this research gap, the authors of this paper conducted studies of the interaction between PCE and silica fume in cement slurries as well as in high-performance concretes (HPC) that have a low w/b ratio. Three PCEs with different molecular compositions were used to study their impact on the properties of concrete (HPC). Therefore, the fluidity and mechanical properties of HPC were evaluated. The impact of the PCE on the shear stresses, plastic viscosity, and zeta potential of cement slurries (containing 10% silica fume as a cement substitute) was also measured.Three types of superplasticizers produced in Algeria were used: Polyflow SR 3600—designated as PCE1, Polyflow SR 5400—designated as PCE2, and Medaflow 30—designated as PCE3. The three polymers are new-generation, non-chlorinated, and based on modified polycarboxylic ether. The molecular weight  and the polydispersity indices (PDI) of the superplasticizers were measured using multi-detector steric exclusion chromatography (SEC) in France . The analytical conditions are presented in 2/kg. The chemical composition of the PC and SF is presented in The Portland cement (PC) that was used in the experimental study was CEM I 52.5 R. It is commercially produced by the Lafarge Company, whose manufacturing site is located in the city of Msila (in the eastern region of Algeria). The microsilica (SF) sample was obtained from Granitex, Algeria. Its marketing name is Medaplast HP, and its specific surface is 23,000 mThe properties of the aggregates are summarized in + ions, which come from carboxyl groups and NaOH, react with each other in a stoichiometric ratio. Therefore, the more NaOH needed to titrate the sample, the more carboxyl groups it contains. The content of carboxyl groups can then be calculated as follows: C(COO–) = content of carboxyl groups (mmol/100 g);CNaOH = molar concentration of NaOH (mmol/L);VNaOH = volume of the NaOH solution used (L); and m = weight of the sample.The acid-base titration method was used to measure the content of carboxyl groups in each polymer sample . The meaThe recipe of the concrete was determined on the basis of the Dreux–Gorisse method while taking into account the ratio of its components , as shown in The slump test was used to evaluate the fluidity of the concrete mix in the case of all the formed HPCs. The dosage of superplasticizer (PC/b) was 1.75%, and it was determined using the VT 550 viscometer. The initial fluidity of the HPC was measured 5 min after mixing all the components. The concrete mix was then placed in a container, which was covered with a plastic film in order to prevent any water evaporation. The second slump test measurement was made after 1 h of concrete maturation. In each case, the concrete mix was stirred for one minute before taking the measurements.2/g) as a partial replacement of cement, the water-to-binder ratio (w/b) was assumed to be 0.35. In this case, for an amount of water equal to 35 g, the mix contains 90 g of cement and 10 g of SF, as well as an added superplasticizer (PCE) in an amount of 0–2.5 wt% of the total cement-based binder. The test was performed at a temperature of 20 ± 1 °C. The rheology of the cement paste was evaluated using a VT 550 viscometer, which is a rotational viscometer. Using this viscometer, the following parameters of cement pastes can be measured: shear stresses (τ) and viscosities (µ), which are obtained as a function of shear rates  were determined using a Malvern ZETASIZER 2000 in materials, processes and environment research unit; Algeria. In a standard experiment, 1 cm2) were prepared according to the EN 206-1 protocol. These specimens were kept for 24 h in molds. After demolding, all the specimens were stored in tap water at 20 ± 1 °C for 3, 7, and 28 days.In order to determine the compressive strength, six cylindrical concrete specimens  and the fluidity assessed after 1 h (slump retention) are shown in  of PCEs . It meanPCE1, with the lowest carboxylic density and molecular weight, exhibited a poor slump and poor slump retention due to the prior adsorption of the PCE on the silica fume surfaces ,29. The PCE2 (with the highest molecular weight) had a bad initial slump and the highest slump retention. The amount of absorbed PCE on the surface of the cement paste increased with a decrease in molecular weight. Therefore, the PCE with a high molecular weight significantly delayed the hydration of the cement. This is due to the fact that the main chain of PCEs adsorbs on different cement particles simultaneously, making them agglomerated and, in turn, hindering the hydration process .The saturation point is the value of dosage beyond which the superplasticizer has no effect on the rheological properties of the cement paste. It was determined using the viscometer VT 550. Each of the polymers  had the same saturation point value, i.e., 1.75, at the tested water-to-binder ratio (w/b). 2+). PCE3 had a high carboxyl content (1.95 mmol/g) and a moderate molecular weight, whereas its polydispersity index  presented a high absolute value of zeta potential in the cement paste (9.7735 mV). This is due to its having the best adsorption capacity with regard to cement particles.The zeta potentials of the cement pastes prepared with the addition of the PCEs (with different carboxylic densities and molecular weights) are shown in The compressive strengths at 3, 7, and 28 days of HPC without superplasticizers are, respectively, 40.2, 45.1, and 50.9 MPa. They are lower than the compressive strength of the HPC with PCEs . TherefoThe aim of this work is to study the compatibility of a polymer with silica fume in HPC. The results show that the chemical structure  of the polymer influences this compatibility. The best chemical structure is a polymer with a moderate molecular weight and high carboxyl density. The PCE with a moderate molecular weight and the highest content of carboxylic groups has the best dispersion , the lowest viscosity, and the highest compressive strength of hardened HPC. Therefore, it can be considered to be compatible with SF. Such compatibility was not observed in the case of the PCE with the low carboxyl density, which was due to the fact that this PCE was adsorbed on the SF and reduced the ability of the cement particles to disperse. Therefore, the workability of the HPC was also reduced.There is a clear relationship between the zeta potential and rheological properties of cement paste and the anionic charge density and molecular weight of PCEs. A good correlation was also found between zeta potential, carboxylic density, and compressive strength.The results from the retention slump tests show that a PCE with a high molecular weight can be applied to precast concrete, whose consistency has to be retained over a longer period of time (until this concrete is delivered to a construction site).The molecular weight of polycarboxylate superplasticizer has a great impact on the properties of cementitious systems. Therefore, PCE3 can be seen to be a perfect polymer in which all the macromolecules have the same length and the same molar mass (PDI close to 1). This, in turn, makes it the most efficient admixture, which was proved by the results of the research conducted.


The complete characterization of wood, with the determination of the 12 elastic constants that represent its orthotropy, is greatly relevant in applications employing structural calculation software programs. Ultrasound allows for such characterization with relative simplicity when compared to other methods. The polyhedron is considered the most appropriate specimen format for allowing the 12 constants to be calculated with a single specimen, and the traditionally used one is the 26-sided polyhedron, which, to be produced manually with more precision in directing the main directions of the wood, needs larger faces. The accuracy of this technique tends to be reduced when increasing the growth rings’ inclination since the waves deviate from the main directions of orthotropy. This research aimed to verify whether it is possible to reduce the polyhedra dimension without affecting the results of the elastic parameters obtained in wood characterization by ultrasound. The results indicate that the dimension of the polyhedron can be reduced without prejudice to the results of the elastic parameters obtained by the ultrasound test and that, in the manual production process of the specimen, the best way to make this reduction is to eliminate the faces unused in the test, changing the polyhedron to 18 faces instead of 26. Reducing the number of faces simplifies the manufacturing process and thus increases the possibility of producing specimens with straighter growth rings and better-directed symmetry axes. Wood is a viable material that is suitable for use in different applications. In civil construction, it has been highly recommended worldwide because of its sustainability since it is a renewable natural resource with low energy consumption and a great contribution to reducing greenhouse gases ,2.Currently, there are structural calculation programs that allow for precise dimensioning of structures, even the most complex ones. However, the accuracy of these tools depends on the insertion of data in a complete and coherent way with the type of material , making the acquisition of these data essential. In addition to civil construction, wood has great importance in the manufacture of musical instruments, which is another example of an area for which knowledge of elastic properties is essential ,6,7,8,9.L, ER, ET), three shear moduli of elasticity , and six Poisson ratios .By reducing the dimensions of specimens, it is possible to obtain more rectilinear growth rings and, thus, get closer to the condition of orthotropy with three main axes of symmetry  that respond differently to the action of loads. The L axis is parallel to the direction of the grain (fiber or tracheid); the R axis is perpendicular to the grain in the direction of the radius; and the T axis is perpendicular to the grain but tangents the growth rings. Thus, for the complete characterization of this material, one must determine twelve elastic constants (nine of them independent): three longitudinal moduli of elasticity  of 830 kg·m−3 and 1090 kg·m−3, respectively, which are values with mean differences of around 2.5% from those obtained in this study. In the case of Cedrelinga catenaeformis, the difference was 22% compared to that obtained by Dias and Lahr  (Equation (2)) was determined using Christoffel’s equations (Equations (3)–(6)). The density values in the equations were those obtained for the pieces used to make the polyhedra . The sti−1, it was possible to obtain the flexibility matrix [S] (Equation (7)), which is associated with the elastic parameters of the material .By inverting the matrix [C]As we used polyhedral specimens of reduced dimensions (18 faces and 26 faces reduced), it is important to analyze whether the theoretical aspects regarding wave propagation in infinite media are being met. For this propagation to occur in infinite media, the distance between transducers (dimension of the piece in the direction of wave propagation) must be a few times greater than the wavelength (λ). For wood, some researchers ,33,34 inBecause of the attenuation of the wave in the wood, the effective frequency (FEF) is different from the nominal frequency of the transducer (f), which, in the case of this research, is 1 MHz. To obtain the effective frequency (FEF), one must obtain the time difference (Δt) between two successive peaks of the wave (FEF = 1/Δt) and therefore the signal must be evaluated  in different directions and planes, and elastic parameters were initially evaluated for normality to ensure the feasibility of using parametric statistics. The multiple range test was used for the comparisons of the results for the traditional polyhedra with 26 faces, the reduced polyhedra with 26 faces, and the polyhedra with 18 faces. For all species studied, the average inclinations of the growth rings were lower for P18, differing more from the P26A samples, which in general presented higher values . The man11 > V22 > V33, V66 > V55 > V44, and V12 45° > V13 45° > V23 45°. In the longitudinal direction of the wood, parallel to the fiber or tracheid (direction 1 or L), the continuity of the anatomical element allows the propagation of waves with higher velocity [Dinizia excelsa, which, with P26N, presented V44 with a value greater than V55, and thus it was the only value eliminated from the statistical analysis. All other values, besides behaving coherently in terms of the theoretical framework, had normal distributions, validating the application of parametric statistical methods. The mean values  of species Dinizia excelsa (13 45°) of species Apuleia leiocarpa .


In this work, cyclic-load tests on reduced-scale corroded reinforced-concrete hollow cross-section bridge piers have been experimentally performed and compared to the results of similar non-corroded piers. Piers were aged by using an imposed electric current and sodium chloride water solution before performing a mechanical cyclic-load test. The corrosion process has been detected with Non-Destructive Evaluation techniques by means of SonReb method (to check concrete degradation) and by measuring corrosion potential (to check steel degradation). The crack pattern was recorded by dedicated cameras, and an LVDT system was set up to monitor the cyclic-load test. Experimental results focused on degradation monitoring and mechanical performance under cyclic loads. During the cyclic-load mechanical test, the first cracks on the piers surface occurred diagonally, inclined at about 45°. This is the consequence of the failure mode change from ductile failure, as expected for slender designed piers, to brittle shear failure. The flexural failure occurred in the case of non-corroded piers. Presented tests can provide a useful contribution of experimental data to analyse the behaviour of corroded reinforced concrete hollow bridge piers, scarcely tested. In particular, the cyclic response can be a useful reference for the proposition/validation of nonlinear capacity models for the evaluation of the seismic capacity of corroded bridge piers. Infrastructures built before the 1980s were designed without taking into account the modern principles of seismic engineering and basic regulations or design codes to counteract seismic loads were available. Hence, the assessment of seismic performance shall be a priority for such infrastructures. The conservation and utilization of the infrastructure network after an earthquake is essential to prevent the interruption of the main rescue lines, given the difficulty for the arrival of relief and often the significant economic loss in the affected areas that are isolated until the reconstruction/restoration.In Italy and in many other countries, a commonly used construction technique for piers is the hollow reinforced concrete (RC) pier that provides, at the same time, strength and reduced mass compared to solid sections. Seismic energy dissipation is assigned in the design of ductile hinges at the base ,2. The nCorrosion of the reinforcement was found to be the predominant deterioration mechanism for RC structures, impacting infrastructure resilience , and thiFew results are available for corrosion of RC bridge piers with hollow cross sections: in particular, the corrosion of steel rebars determined a significant reduction in the lateral strength, secant stiffness and energy loss per cycle of the piers, both experimentally ,25 and nIn addition, Structural Health Monitoring (SHM), focusing on damage investigation with non-destructive evaluation techniques, has been adopted to monitor concrete degradation , reinforThe reduced availability of experimental results on hollow-cross-section RC piers induced the authors to perform this experimental program. In this study, the analysis of the structural response of the hollow piers (both circular and rectangular) of bridges, under cyclic forces at the upper end and influenced by the aging process at the base of the pier, is performed both by means of non-destructive monitoring and mechanical test evaluations.2 and an internal hole cross section of (0.20 × 0.40) m2. The longitudinal reinforcement consists of two layers: an external one consisting of 18D8 and an internal one consisting of 10D8, while the D3 stirrups were positioned at a distance of 12 cm  of 2.55 m (1.50 m stem only) with an external diameter of 0.55 m and an internal diameter of 0.35 m. The longitudinal reinforcement consists of 24D8 with D3 stirrups at 12 cm spacing and 1,7 cm concrete cover .3 for the rectangular pier and (75 × 75 × 30) cm3 for the circular pier.The load head dimensions are (60 × 80 × 30) cm3.In the investigation and to ensure a fixed constraint during the mechanical test after the aging process, an oversized base was considered with the following dimensions (120 × 120 × 75) cmym, of 505 MPa and smooth transverse bars with average yield strength, fym, of 655 MPa.Several casts were used for the construction of the piers. The base was made of concrete class C35/40 and ribbed bars class B450C; the stem and the load head made of concrete with 20 MPa average compressive cubic strength at 28 days, longitudinal ribbed bars (B450C), with average yield strength, f2 by means of potentiostat–galvanostat) such as to induce bar consumption of about 200 μm/year (1.00 mA/m2 induces 1.17 µm/year of corrosion penetration) [In order to investigate the seismic response of corroded piers, specimens were subjected to an accelerated ageing process using 3.5% sodium chloride solution  ,39 for eIn order to assess the evolution of the ageing process, non-destructive tests were carried out using the SonReb method and measurements of the corrosion potential, both in areas close to the corroded portion , and, for control purposes, closer to the head of the pier stem  a.The load tests were carried out through a hydraulic actuator (thrust capacity of 500 kN in compression and 300 kN in tension) under displacement control; horizontal displacement cycles under almost static conditions were applied along the centre line of the pier head. With a hinge constraint, the rotation between the actuator and the pier was allowed during the test.Three D16 nominal high strength post-tensioned steel strands were fixed inside the foundation at the base.; on the other side the strands were loaded by means of a hydraulic jack (capacity of 500 kN) on the top of the pier to apply a constant vertical load to the pier during the cyclic horizontal loading. The vertical load was provided by a rigid steel plate on the pier head that allowed the vertical load to be distributed. The foundation was fixed to the strong laboratory floor with other 4 post-tensioned steel bars. The illustration of the test configuration is shown in 4 are shown in 4 (negligible corrosion) are reported with green colour, values between −200 mV vs. Cu/CuSO4 and −350 mV vs. Cu/CuSO4 (corrosion) are reported with yellow colour, while values below −350 mV vs. Cu/CuSO4 (corrosion at high speed), are reported with red colour. After 26 days of testing, the recorded values are higher than −100 mV vs. Cu/CuSO4 for the entire length of the bars, indicating that the aggressive agents have not yet triggered the corrosion process. After 59 days of testing, the area close to the aggressive agents presents values that tend to yellow and red for all bars . The following measurements  show that the degradation is progressively also affecting the reinforcement sections most likely to be impacted by aggressive agents, highlighting important criticalities in the sections closest to them, due to the high recorded potential values.During the period of the ageing process, the ultrasound velocities were detected and sclerometer tests were performed, three times, in five points named (1B-2B-3B-1A-3A), arranged according to the scheme of 4 were carried out  and two in the upper zone (3A and 4A). In particular, point 1A is placed in the area in direct contact with aggressive agents, point 2A is chosen at a distance of 30 cm from the aqueous solution, point 3A is placed at 20 cm below the loading head and point 4A at 55 cm from the head. These tests were carried out at time 0 (28 days after casting), 90 days and 120 days. In ried out , for corried out b mapped Destructive tests were performed by means of a cyclic load at the head of the piers to evaluate the overall behaviour of the piers, after the aging process.The cyclic test was carried out under displacement control. The test was divided as follows: for the rectangular hollow pier, the designed test protocol indicated in A wire potentiometer system was used for displacement monitoring. The used system allowed for the monitoring of the actual displacement to be recorded at the head of the pier. LVDTs (linear potentiometers) were used, positioned in diagonal, in order to estimate the contribution of shear to the displacement, and others in order to control out-of-plane displacement of the pier .The force-displacement diagram was constructed using average force data (recorded by the load cell at the actuator) and displacements at the top of the pier.max is the positive force at Δmax (maximum displacement), Fmin is the negative force at Δmin (minimum displacement).For the determination of the overall behaviour of these elements, the well-known secant stiffness modulus, Es, has been taken into account as the slope of the line passing through the two peak points, negative and positive, of the same load-unloading cycle, calculated with Equation (1):χ, is calculated with Equation (2):max and Δminvalues recorded by the instrumentation positioned along different sides of the pier , but placed at the same height, is averaged.In next moment-curvature diagrams, the curvature, gaugeL is the distance between the measuring points; therefore, 600 mm, D, is the distance between two measuring points on the same side positioned at 0.06, 0.66 and 1.26 m, respectively, from the base of the hollow pier stem. In addition to the symbols presented for Equation (1), For completeness of discussion, a cracking analysis was carried out by inspecting the images taken by a camera in front of the pier during the cyclic test. Through the identification of maximum displacement values, the related photographs were classified and correlated. Twelve peak points for positive and negative loads were identified for each of the loading-unloading cycles. The images taken during the first three drifts do not show visible damage to the piers and are considered, therefore, not significant; those taken afterwards  are shown. The state of the rectangular pier at the beginning of the test is shown in The first crack occurs at the fourth drift cycle, in a pre-peak phase at 145.66 kN and a displacement of 6.65 mm. At drift four, the first crack occurs, in a pre-peak phase at 83.30 kN and at a displacement of 12.80 mm. In addition, in The analysis of the crack pattern shows a typical behaviour in coupled bending and shear condition. Both piers have been designed and manufactured with a reduced level of longitudinal reinforcement to have a ductile behaviour common to slender members, hence failing in bending, as occurred in the case of the non-corroded pier . The effThe non-symmetric behaviour between push and pull side of the test is mainly due to the reduction in diameter  of longitudinal bars. However, the flexural capacity is marginally reduced (about 5%) due to corrosion of longitudinal bars and cyclic effect; in fact, the reduction in the longitudinal bar diameter due to corrosion is about 6.5% (estimated from imposed electric current and related corrosion penetration) ,39, and cV accounts for shear carried by concrete, sV for the truss mechanism where shear is carried by the reinforcement and pV is the contribution provided by an inclined axial load strut, i.e., the compressed portion of the cross section can transmit the shear force at the basement. Each contribution in Equation (3) is provided by the following formulae (Equations (4)–(6)).cf′ is the concrete compressive strength, yf is the yield strength, gA is the gross area of concrete cross section, vA is the cross section of transverse reinforcement, θ is the cracking angle (suggested to be assumed as 30°), D is the section height, c is the neutral axis depth, cov is the concrete cover, s is the spacing of transversal reinforcement, vL is the shear span equal to pier height for a cantilever pier.On the contrary, the corrosion of the stirrups made of thin transverse reinforcement bars is the main reason of the failure mode, changing from desired flexure to brittle shear due to corrosion effect. To support such experimental outcome, the shear capacity evaluation is based on the Kowalsky and Priestley  model. Aα and β of the Equation (4), reported in Equations (7) and (8), account for aspect ratio and longitudinal steel ratio, respectively. Term γ in Equation (9) accounts for the degradation of the concrete shear resisting mechanisms with flexural ductility demand.Terms sV. Based on experimental results, a shear crack opens clearly during the former seventh push cycle at a drift of 3.53% , but they did not contribute to the shear capacity. Therefore, the .74% see  and corr4 for the entire length of the bars at the beginning of the process to values lower than −350 mV vs. Cu/CuSO4, revealing high corrosion rates, firstly, close to the aggressive agents and also far from them at the end of the process. These results confirm the predictability of corrosion degradation of steel and concrete by means of such techniques.Experimental results of cyclic-load tests on reduced-scale corroded reinforced-concrete rectangular and circular hollow cross-section piers are analysed and compared to the results of similar non-corroded piers. The piers were corroded by using electric current and sodium chloride water solution before the mechanical cyclic-load tests. The corrosion process has been detected by performing the SonReb method (to check concrete degradation) and by measuring corrosion potential (to check steel degradation). Such non-destructive evaluation techniques revealed the degradation of concrete with a significant reduction in direct-transmission ultrasonic-wave velocity started after about 60 days from the beginning of the (accelerated) ageing, with clearly different trends close and far from the corroded portion. Similarly, corrosion potential of bars turns from safe values higher than −100 mV vs. Cu/CuSOCorrosion induced a reduction of section in longitudinal and transverse bars, reducing both flexural and shear capacity. The transverse bars have lower section and concrete cover compared to longitudinal ones, hence are the most exposed steel reinforcement to corrosion with larger capacity losses.After the cyclic-load test procedure, the first cracks on the piers’ surface occurred diagonally inclined at about 45°. This is the consequence of the failure mode change from ductile failure, as expected from slender designed piers with low longitudinal reinforcement ratio, to brittle shear failure, even with limited corrosion penetration. In fact, flexural failure occurred in the case of non-corroded piers. The global lateral capacity loss occurred both in terms of force and significant reduction in terms of ductility at low drift ratios.The crack pattern was recorded by dedicated cameras and an LVDT system was set up to monitor the cyclic-load test. Experimental tests show that the behaviour of the piers, as expected, is almost similar for both kinds of cross-section.Presented tests can provide a useful contribution to analyse the behaviour of corroded reinforced-concrete hollow bridge piers. In particular, the cyclic response can be a useful reference for the proposition/validation of nonlinear capacity models for the evaluation of the seismic capacity of corroded bridge piers.


Background and Objectives: Practitioners of martial arts such as Taekwondo are likelier to experience back pain during training or competition. As the back pain of taekwondo athletes shows various symptoms depending on the athlete’s characteristics, such as technique and movement, a case study was conducted to verify the intervention effect suitable for individual traits. We examined the effects of a complex pain control program on pain, mechanosensitivity, and physical function in a Taekwondo athlete with recurrent low back pain (LBP). Materials and Methods: A Taekwondo athlete with LBP was recruited from D University, Busan. The intervention program was performed for 45 min twice a week for 3 weeks, and the patient was followed up with after 2 weeks. The numerical rating pain scale (NRPS), pain pressure threshold, mechanosensitivity, and Oswestry Disability Index (ODI) scores were measured before and after the intervention. Therapeutic massage and nerve stimulation therapy were performed. Lumbar flexion, extension, and rotation were performed in the movement control exercise group, whereas the sliding technique, a neurodynamic technique of the tibial nerve, was applied in the neurodynamic technique group. This effect was verified by comparing the average measured values before and after the intervention. Results: Pain (NRPS) and mechanosensitivity reduced, range of motion and tactile discrimination abilities improved, and physical function (ODI) improved. The effect of the improved intervention lasted 2 weeks. Conclusions: These results indicate that application of complex pain control programs considering the four aspects of pain mechanisms for 3 weeks can be an effective intervention in Taekwondo athletes with recurrent LBP. With the recent increase in the intensity and frequency of sports participation in the general population, the incidence of low back pain (LBP) has continuously increased in modern society . Under tRecurrent LBP (RLBP) frequently occurs among athletes performing martial arts sports, including Taekwondo, who predominantly perform high-intensity and repetitive training involving sparring with partners, an activity that induces various injuries. The time spent on recovery is short, and repeated overloading is applied to the lumbar spine . As suchAthletes commonly spend considerable time and money on surgery and rehabilitation therapies to control the symptoms of RLBP . PreviouThe current case study involved subjects who had experienced repetitive back pain at least twice in the past six months due to high-intensity training involving repetitive kicking movements for more than 5 h, five days a week, accompanied by pain.He is a 23-year-old subject with RLBP from D University in Korea and a registered athlete with the Korea Taekwondo Athletes Association with more than ten years of experience. He was diagnosed with L5~S1 disc spondylosis through MRI at a general hospital in Busan in July 2020. The subject’s Visual Analogue Scale (VAS) score was 5 points, and his ODI (Oswestry Disability Index) score was 8 points, which belonged to the selection criteria of previous studies . In addiThe subject used a motion analysis device  to attach sensors to S1 and T12 and conduct motion analysis. He had lumbar spine LOM due to radiating pain. In addition, radiating pain was observed in the left leg during the SLR test while maintaining the lumbar curve in the supine position. The subject was diagnosed with back pain in the hospital and did not receive any medications or treatment until the trial intervention was conducted.The evaluation and intervention in this study were conducted by different physical therapists with more than six years of clinical experience. This study was approved by the Institutional Review Board of Dong-Eui University (DIRB-202202-HR-R-02). Subjects received an adequate description of the study purpose and intervention .Before the intervention, tactile discrimination (TD) and mechanosensitivity  were measured in the given order. Measurements were repeated every week during the 3 weeks of intervention and 2 weeks after the completion of the intervention to monitor the continuous effects via a re-test. Among the measured variables, TD was used to assess changes in skin sensation in the area of pain related to chronic lumbar pain. For the measurement, nine blocks were drawn on the patient’s back, where the patient selected three pieces of paper indicating numbers 1–9 that had been randomly arranged twice; the patient was placed in a prone position, where the TD was obtained as the center of each block was pressed. Triplicate measurements were performed, and the mean was calculated for the analysis .Mechanosensitivity indicates the sensitivity of peripheral nerves to movement and was used in this study to assess the changes in nerve sensitivity induced by the intervention . Lumbar The VAS score and ROM at P1 and P2 were measured each week during the period of intervention, and before the intervention, the VAS score and MA were measured simultaneously on the ROM at P1 and P2. The ODI was used to assess pain-related discomfort during daily activities.In the measurement of TD, a total of nine squares, three along a 5-cm width and three along a 5-cm length, were drawn on the lumbar area based on two-point discrimination, where two points were sensed as a single point to define the size of one square. Each square was marked by numbers 1–9, and the rater guided the patient to be aware of the squares from 1 to 9 for 5 min and to select a random sequence of numbers twice for each number on the square. Using a pen to press the center of each square indicated by the selected sequence of numbers, the rater asked the patient to correctly guess the number of times the square was pressed. After all three sequences of numbers selected by the patient were tested, the rater converted the number of times the patient had correctly guessed into a score and estimated the mean ,20,21,22In the ASLR test, the point at which the patient first sensed pain was set as P1, and the point at which he sensed the maximum pain to be unable to produce further changes in the ROM was set as P2. The intensity of pain at P1 and P2 was expressed by the patient to the rater as a VAS score, and the mean of triplicate measurements was used for the analysis ,24,25.In the ASLR test, the patient was instructed to maintain his ankle at a 90° angle to prevent lumbar flexion and to measure the mechanosensitivity of the lower limb during pure hip flexion. In addition, PBU  was used to control the effect of lumbar flexion on the nerves going to the legs. The pressure of PBU was maintained at 40 mmHg. The margin of error for the pressure change during ASLR was set at 10 mmHg.The electrodes for surface electromyography  for the measurement of MA were attached to the origin of the biceps femoris and semimembranosus muscles, as well as to the muscle belly at a two-third position between the part and insertion. The distance between the two electrodes was 2 cm. For the lateral gastrocnemius, the electrodes were attached to the muscle belly 2 cm below the knee joint . The MA MyoResearch Master Edition 3.10  was applied to analyze the MA data. The extraction speed for the surface electromyography signals was set at 1024 Hz, and the interference was removed using a low-pass filter at 20–350 Hz.The root mean square (RMS) values measured for 3 s for each muscle (excluding the first and last seconds) were used as variables. For MA, triplicate measurements were performed at P1 and P2, and the respective means were used. Based on the initial ROM values at P1 and P2, the differences in the mechanical sensitivity of the biceps femoris, semimembranosus, and lateral gastrocnemius were measured each week. To normalize the measured values, the values of maximum voluntary isometric contraction (MVIC) for each muscle before the intervention were used to calculate the %MVIC  Figure .During ASLR (Active straight leg raise), the rater measured the changes in hip joint ROM and ROM at P1 and P2 by attaching a motion analysis device  to L3, the center of both posterior superior iliac spines, a one-tow point at the leg, and a one-tow point at the tibia and center of the talus. The ankle joint angle was maintained at 90° to identify the pure angle of the hip joint. The VAS score, ROM, and MA were simultaneously measured ,26.The patients completed the questionnaire at onset and each week before the intervention. The questionnaire comprised the following 10 items investigating daily activities: pain intensity, personal care, lifting, walking, sitting, standing, sleeping, sex life, social life, and traveling. Each item is rated on a scale of 0–5, and the patient could respond yes or no to the four questions of each item regarding their personal status in the past 24 h .The intervention in this study to test the complex pain programs based on four aspects of pain mechanisms comprised three sets of 5-min TD training, 10-min neurodynamic exercise, 15-min movement control exercise, and 10-min therapeutic massage and stretching. The total reaction time was 40 min. The intervention was administered twice weekly for three weeks, considering the subject’s training and competition schedule . The patOn the patient’s back, the rater prepared a total of nine blocks, three each with a 5 cm width and length. Each block was assigned a number from 1 to 9. The rater then pressed the center of the block with a pen and showed the patient an image of the block numbered 1–9. The goal is to correctly guess the pressed block. The back of the pen was used to press the numbered blocks, and the patient was educated for being familiarized with each of the nine numbered blocks. During this period of 5 min of training, the patient was repeatedly informed of the correct number of blocks being pressed with repeated stimulation on the block in the case of guessing an incorrect number until he was correctly aware of all nine blocks  Figure .The rater provided manual shoulder support to maintain pure cervical flexion. While maintaining extension of the toe and ankle, the patient performed knee extension until the leg muscles felt fully stretched or started to cramp. The patient performed neck extension immediately before the muscle was stretched or clamped for further knee extension. This was followed by cervical and knee flexion to complete three sets of sliding techniques, with each set comprising 10 exercises and 1 min of rest  Figure .Training involved flexion, extension, and rotation. During training in the flexion direction, the patient was guided to maintain a neutral pelvic position in the quadrupedal position and to move the hip joint from 90° to 120°. During training in the extension direction, the subject was guided to maintain a neutral pelvic position up to 120° flexion of both knees, as the PBU  was used, and a pressure of 40 mmHg was maintained on the abdomen in the prone position. During training in the rotation direction, the patient was guided to maintain a neutral pelvic position in the side-lying position up to 15° abduction of the hip joint  Figure .To increase the flexibility of the tensed muscles, therapeutic massage was performed on the quadratus lumborum and erect spine muscles, followed by 10 min of hamstring stretching ,31.Compared with the pre-intervention scores, the TD point (TDP) scores after the 3-week intervention increased by 21.43%, while scores at the 2-week follow-up increased by 33.33% .The VAS scores at P1 and P2 during ASLR decreased after the 3-week intervention compared to the initial scores by 40% at P1 and 20% at P2 after the 3-week intervention compared with the initial scores. The scores at the 2-week follow-up decreased by 48% at P1 and 34.29% at P2 compared with the initial scores, and the levels were subsequently maintained .The ROM scores at P1 and P2 during ASLR increased following the 3-week intervention by 16.79% at P1 and 13.01% at P2 compared with the initial scores. The scores during the 2-week follow-up after the intervention increased by 13.42% at P1 and 8.85% at P2 compared with the initial scores, and the levels were subsequently maintained .The electromyography activity scores of the semimembranosus, biceps femoris, and gastrocnemius muscles for the P1 and P2 ROMs in the early stage of ASLR decreased after the 3-week intervention compared with the initial scores by 22.37% at P1 and 48.82% at P2 in the semimembranosus muscle, 13.77% at P1 and 46.76% at P2 in the biceps femoris muscle, and 14.78% at P1 and 18.37% at P2 in the gastrocnemius muscle. The scores during the 2-week follow-up after the intervention decreased by 35.53% at P1 and 42.74% at P2 in the semimembranosus muscle, by 31.77% at P1 and 62.3% at P2 in the biceps femoris muscle, and by 29.14% at P1 and 38.42% at P2 in the gastrocnemius muscle, compared with the initial scores, and the levels were subsequently maintained in all three muscle groups .Regarding the ODI, the scores after the 3-week intervention were 25% lower than the initial scores, and the scores decreased by 37% compared with the monitor post-intervention levels during the 2-week follow-up  Figure .This study aimed to determine the effects of complex pain control programs involving the treatment of four of five pain mechanisms on TD, tissue mechanosensitivity, and lumbar functions in Taekwondo athletes with recurrent LBP.The inclusion criteria for patients with RLBP in previous studies were individuals who complained of pain at least twice in the past 6 months, with a level of pain estimated as a VAS score ≥ 5 and an ODI score of ≥5, while the exclusion criteria were individuals with acute lumbar pain, spinal fracture, and a history of surgery, spondylolisthesis, or spinal tuberculosis . The samAdvances in neuroscience and brain imaging research have allowed further research in the human brain, which have reported that the brain undergoes functional changes when a part of the body experiences pain . Pain-inPrevious studies have shown that motor control training leads to the control of compensation movement via education of the order of muscle recruitment, thereby reducing the load on the joint caused by the compensation movement ,35. MotoMechanosensitivity indicates the level of nerve tissue activity in response to a mechanical force . A previThe results of this study showed that an intervention combining neurodynamic, movement control, and TD training facilitated a reduction in pain at P1 and P2 when the patient performed SLR. The angles at P1 and P2 that were reassessed after the intervention both showed an increase, which was interpreted as an increase in ROM. In addition, MA was shown to decrease the angles of the hamstring and gastrocnemius muscles, and the altered level from the initial pre-intervention level was maintained for 2 weeks post-intervention. In a previous study, motor control exercises could discriminate between the normal alignment of the body and isolated motions at each segment to disperse the load on each segment . PreviouIn several previous studies, the ODI was used to objectively measure pain in patients with LBP and to examine the functional levels associated with functional and cognitive impairments ,45,46. PThe findings of this study suggest that complex pain control programs are effective for the management of pain in Taekwondo athletes with LBP. Through the management and improvement of the four pain mechanisms, the pain-related reduction of mechanosensitivity in the surrounding tissues and body’s functions and abilities to discriminate the segments could be improved. Based on these results, it is predicted that the use of a complex intervention based on pain mechanisms rather than a single perspective, even in the early days of rehabilitation, would be effective at promoting the functional recovery of training athletes with RLBP.This study had some limitations. First, by applying for the intervention program, only secondary functional changes were confirmed without confirming changes in the activity of the back muscle. Second, the effects of a single intervention program could not be confirmed by confirming the impact of a complex intervention program. Third, an approach that reflects psychological and social factors related to chronic pain through repeated trauma and injury in Taekwondo players has not been investigated through various pain mechanisms.Therefore, further studies are needed to determine the long-term effects of complex pain control programs based on pain mechanisms, including psychological and social factors.Complex pain control programs incorporating these four aspects of pain mechanisms can reduce pain and mechanosensitivity, improve ROM and TD, and enhance physical function. As such, we propose that such complex pain control programs could be effective interventions for Taekwondo athletes with LBP.


In the November 2000 issue of this journal, the editorial made a prediction that the decreasing trend of cardiovascular death rates in Brazil that had been seen in the 1990s would flatten out, as the first effect of the increasing prevalence of obesity in this country.To explain this apparent paradox, hypotheses such as the notion that the body mass index is not a good surrogate of adiposity as a risk for atherosclerosis and high blood pressure have been put forward.th revision of the International Classification of Diseases (ICD-10), in which both diabetes and a well-defined final cardiovascular event can be considered to be the underlying cause of death. This nosological artifact has been found not to be limited to Brazil and has also been shown in countries like Mexico and the United States.The rationale for considering that there may be a classification bias is that, in most cases, people with diabetes die due to heart disease and stroke. However, this has been changing since 1996, with the adoption of the 10th revision (ICD-9) from 1980 to 1995 and thereafter using ICD-10. I analyzed all cardiovascular diseases , coronary heart disease  and stroke (code: 460-8 and I-61-69), separately. Furthermore, I added the cases with diabetes (codes: 205 and E-10-15) to all the cardiovascular diseases, thus creating a category called “cardiometabolic deaths.”To test this hypothesis, I analyzed the trends in assignment of the underlying cause of death over a period of three decades from 1980 to 2011, according to gender. This analysis concentrated on the age group from 30 to 69 years, because there are few cardiovascular deaths at younger ages , and because a high proportion of such deaths among individuals over the age of 70 years cannot be compared due to comorbidities. Since Brazil adopted ICD-10 only in 1996, mortality data were classified according to the 9The investigation plan included: (1) review of the numbers in all the categories above, with calculation of the proportion of deaths relating to diagnoses that were listed as ill-defined causes of death; (2) adjustment of all crude death rates using the World Standard Population; (3) calculation of temporal changes to death rates using the Joinpoint 4.1.1 software.,These temporal changes to death rates in Brazil show that the decline is occurring in the whole country, despite the shifting of nosological causes from cardiovascular diseases to diabetes. The faster decline of stroke death rates, compared with CHD, reveals that the phase of “delayed cardiovascular epidemiological transition” has ended.


Background and Objectives: Gastrointestinal tract infections caused by Clostridioides difficile bacteria are diagnosed in pediatric patients with increasing frequency. Children treated at pediatric units are a group of patients at high risk of this infection; therefore, appropriate differential diagnostics and an individual approach to every case are of particular importance. The goal of the study was to assess the clinical parameters of patients with a confirmed CD infection and colonization. Materials and Methods: Every positive case was subjected to a retrospective analysis based on medical history and an infection notification note. Results: Positive results were obtained for 30 patients, among whom the results of 18 patients were considered to justify the diagnosis of an infection. In the remaining patients, treatment was not initiated in only three cases. Cases were detected where treatment was initiated despite the lack of sufficient clinical evidence. Conclusions: This study demonstrates that there are many factors that result in a high risk of the occurrence of CDI in oncology patients, such as antibiotic therapy, multiple hospitalizations, and myelosuppression. Clostridioides difficile (CD) constitute a growing public health challenge, both clinically and economically [Clostridioides difficile infection (CDI) [Infections caused by toxigenic strains of omically . Pediatron (CDI) . On the on (CDI) . On the on (CDI) . The bason (CDI) . Radiothon (CDI) . The useon (CDI) . A decreon (CDI) . Signifion (CDI) . The per9/L to 1.5 × 109/LGrade 1—2.0 × 109/L to 1.0 × 109/LGrade 2—1.5 × 109/L to 0.5 × 109/LGrade 3—1.0 × 109/LGrade 4—<0.5 × 109/L) with a simultaneous increase of the body temperature above 38.3 °C leads to the occurrence of a neutropenic fever [Clostridioides difficile strains and by other pathogens present in the hospital environment [The risk increases with the duration of neutropenia ,11. The ic fever . This coic fever . The lowic fever . Additioic fever . Cytostaic fever . In pediic fever . The tubic fever ,20. The ironment . Surgicaironment . The mulironment ,24. Admiironment ,26. In tironment .Clostridioides difficile infections at a pediatric oncology department in 2020, looking at the administered treatment, the clinical parameters accompanying the disease, and the impact of the infection on the course of treatment of the primary disease.The objective of the study was a clinical analysis of cases related to The studies were conducted in a pediatric hospital qualified as a 3rd reference level, located in central Poland. The results obtained in 2020 (time range of 1 January 2020 to 31 December 2020) from patients hospitalized at an oncology department were subjected to a retrospective analysis for toxigenic variants of CD. On the basis of the collected medical documentation, an assessment of risk factors related to the CDI and of the clinical state of the patients was performed, taking into account the treatment used.C. difficile and immunochromatographic assays for the detection of the antigen of glutamate dehydrogenase (GDH) and TcdA/TcdB toxins. In the case of a positive result for glutamate dehydrogenase and negative tests for TcdA/TcdB toxins, the material was cultured anaerobically on agar plates, and then from the obtained positive culture, a repeated immunochromatographic assay for CD toxins was performed. Based on the results of laboratory tests, a group of patients with positive results for toxigenic CD strains was identified. This group was subjected to a detailed review using the methods of retrospective analysis.Tests for CD were requested as part of the diagnostic and treatment process based on the clinical symptoms observed, that is, the presence of diarrhea with varying strength, vomiting, stomach pain, tenderness, fever, general weakness, and blood in the stool. Laboratory diagnostics consisted of testing the stool samples with a two-stage algorithm for the detection of toxigenic strains of CDI cases were defined as positive in the case of a clinically significant stool (3 or more loose stools within 24 h). Due to group specifics and the severe general condition of the patients, every case of confirmation or exclusion requires an individual assessment by the medical team and the infection control team. There were special difficulties related to the appropriate qualification of patients under 2 years of age. First, it was necessary to exclude other infectious and non-infectious determinants that could result in similar clinical symptoms. The cases of hospital-acquired CDI (HA-CDI) were defined when the first clinical symptoms occurred within 48 h and were related to the hospital stay. The cases of community-acquired CDI (CA-CDI) were specified for patients with symptoms that appeared directly after admission (less than 48 h) and were not related to hospital care.Elements of descriptive statistics were used in data analysis. The qualitative (category) variables were described using size (n) and frequency (%). The measurable variables were described with the following basic parameters: arithmetic mean, standard deviation (SD), median, and minimum and maximum values (min. and max.). In order to test the relationships between category variables due to a low number of study subjects (n = 30), Fisher’s exact test was used for 2 × 2 contingency tables, and a chi-square ML (maximum likelihood) test was used for contingency tables larger than 2 × 2. In order to check the significance of the difference between the two studied groups, the Mann–Whitney U test was used if the criterion of normal distribution was not met.p-value of p < 0.05 was assumed to be statistically significant. Statistical calculations were performed using the Statistica 13.0 and Stata/IC 12.1 software.The Clostridioides difficile. The oldest patient was 15 years old, and the youngest was 5 months old. Patients under 2 years of age constituted 53.3%, whereas patients above 2 years of age constituted 46.7%. In the studied group, 66.7% were male (20) and 33.3% were female (10).The study group consisted of 30 patients hospitalized in 2020 at an oncology department of a pediatric hospital, in whom positive results were obtained for toxigenic strains of In Clostridioides difficile infection, whereas cases of community-acquired CDI were established in 9 patients as well, as reported by the Hospital Infections Control Team. Children below 2 years of age constituted, respectively, 3 cases of hospital-acquired infection and 4 cases of community-acquired infection with CDI. A group of 12 patients was classified as colonized based on a more comprehensive clinical analysis. Children below 2 years of age constituted 75% of this group. In this group, the detection of a toxigenic strain of CD was not considered to be the main determinant responsible for the gastrointestinal ailments due to the presence of other influencing factors. The main exclusion factors included, among others, a rotavirus infection, a norovirus infection, food intolerances, and primarily states after the administration of chemotherapy that cause disorders of reabsorption of fluids in the intestines and damage to the surface of the epithelium. The studied group over 2 years of age with a positive result for toxigenic CD constituted 14 patients, out of which 9 were male. Based on clinical symptoms and microbiological results, a diagnosis of hospital-acquired CDI was made in six patients. Colonization was established in 3 patients, whereas community-acquired CDI occurred in 5 patients. In 2020, the total number of hospitalizations at the oncology unit amounted to 1826, which provides an average occupancy of 51.62%, with the number of beds being 57. The average hospitalization time for the entire hospital unit, not including single-day stays, was around 3.6 days. The number of microbiological tests for CD performed during the entire year 2020 was 175 samples from 79 patients. During 12 months, a total of 37 positive results were obtained in a group of 30 patients. In 14 patients, it was the first and only diagnostic test for CD. In this group of 30 oncological patients, repeated positive results were obtained in 2 children in a period of over 4 weeks from the last test and in 2 subsequent patients in a time interval not exceeding 3 weeks from the previous test. Based on the obtained results in 9 patients, the infection was classified as a hospital-acquired The number of hospitalizations in the entire studied group at the turn of 12 months amounted to, on average, 11.5. In the case of patients with confirmed CDI, this value was in the range of 1 to 22 (on average 10.6), whereas in the second group, the number of hospitalizations was from 4 to 22 (on average 12.9). The average duration of hospitalization was, respectively, 24.77 days (for HA-CDI patients), 16.77 days (for CA-CDI patients), and 9.75 days (for colonized patients). In 14 out of 18 cases, admissions of patients with confirmed CDI were under an emergency procedure, out of which 7 were admitted with a life-threatening condition. In 7 out of 12 cases, colonized patients were admitted to the unit in a planned manner for their scheduled treatment. The duration of hospitalization of patients admitted in a planned manner (for the entire studied group) mostly did not exceed 7 days (6 out of 11 cases). In the 30 days preceding the detection of a toxigenic CD variant, antibiotic treatment was administered to 25 patients. Antiviral treatment was used in 3 patients (2 colonized patients and 1 with CA-CDI). In one case, it was related to a Varicella-Zoster virus infection (a patient from the colonized group). Antifungal treatment was administered in 10 patients (7 with confirmed CDI and 3 colonized patients), with fluconazole being the active substance used in 6 patients.In the case of patients with a confirmed CDI, for 11 of them, the first-line drug was metronidazole. It was also the drug most frequently used in the group of colonized patients (5 out of 12 children). In the case of the remaining colonized patients, 4 were administered rifaximin (2 cases described above), and no CD treatment was administered to 3 of them . Vancomycin was used solely in the group of patients with confirmed CDI—originally 3 patients—and in 2 children, it was necessary to change the metronidazole used in the first-line treatment to vancomycin (patients with a relapse of the CDI).9 (high risk of complications). After clotting was stabilized, the therapy was continued until the patient was transferred for a transplant. The second patient was an 8-month-old infant with a diagnosis of neuroblastoma, ANC = 170/µL , in whom a norovirus infection was detected, a 14-day rifaximin treatment was administered, and the patient exhibited severe malnutrition (Cole index was 62.4% at BMI = 10.74).The first case of administration of rifaximin for CD colonization was in a patient who was being prepared for megachemotherapy before a planned auto-HSCT (autologous haematopoietic stem cell transplant) procedure. The child was admitted for an emergency procedure with thrombocytopenia and symptoms of bleeding diathesis after a recent surgical procedure . The neutrophil count at hospital admission was 0.14 × 10When analyzing patients in whom treatment for CD was not administered, it should be indicated that in one patient the symptoms resolved after the antibiotic was withdrawn and in another after cytostatic medication was withdrawn (children below 2 years of age). For children above 2 years of age, only one patient colonized by tox CD was not subjected to treatment. It was a 5-year-old girl with a diagnosed malignant cerebellum cancer, admitted for another cycle of supportive chemotherapy after a recent zoster treated with acyclovir . In the case of two patients identified as carriers, clinical data included in the medical history did not indicate the need for treatment for CD . In addition, information was provided that diarrhea occurred immediately after the administration of chemotherapy.In the analyzed group, 15 patients required transfusions of blood components, with as many as 11 patients diagnosed with CDI (7 patients admitted in an emergency procedure). In the colonized group, the transfusion of blood components during an ongoing hospitalization was necessary in 4 patients, out of which in 1 the absolute neutrophil count did not exceed 500/µL (high risk of a neutropenic fever) and in one it was significantly lowered and did not exceed a level of 1000/µL. A total of 8 patients were admitted for an emergency procedure, and as much as half of this group required transfusion of blood components . In seven patients with confirmed CDI, a high risk of the occurrence of neutropenic fever was present. The C-Reactive Protein was within limits in 11 patients (5 colonized patients and 6 children with CDI). A significant increase in this parameter was noted in five patients. Hypoproteinemia requiring the administration of preparations of albumin occurred in 7 patients, out of whom as many as 5 had CDI. Two patients with HA-CDI were overweight: a boy of 5 with a lymphoblastic lymphoma, in whom a post-steroid Cushing’s syndrome occurred as a result of treatment (without assisted feeding), and a boy of 2 with a CNS cancer .In nine children, invasive surgeries were performed in the last 3 months . In this group, six children had a full-blown CDI infection. In the case of one of the HA-CDI patients, bowel obstruction has occurred , which also required a surgical intervention. The patients being administered chemotherapy (8 patients with HA-CDI) all had a surgically implanted central venous access device. In the entire group, trepanobiopsy was conducted on five patients. Radiotherapy related to current hospitalization was conducted in five patients, four of whom were in the colonized group.In the study conducted, nine patients were qualified as having HA-CDI based on the time at which the clinical symptoms occurred. In every patient, clinically significant diarrhea has occurred . The course of the CDI in 7 patients was established as mild, whereas in 2 it was moderate. In one patient, a previous transplant was noted as a significant risk factor. Exogenous infection was established in one patient (contact infection). The presented patient population is burdened by a series of factors that facilitate the infiltration of the pathogen and then the development of the infection. The literature data indicate that the risk of the occurrence of CDI in pediatric patients treated at oncological units is as many as 15 times higher compared to the general pediatric population, whereas the risk of the occurrence of CDI may apply even to 17% of children who receive HSCT ,29,30. TWhereas in the case of a patient with end-stage neoplastic disease, the course of a CD infection has negatively impacted the general condition of the patient despite the use of palliative therapy intended to increase the comfort of life. In the discussed case, it is difficult to unequivocally consider CD to be a factor impacting shorter survival due to the progression of the disease.In a study we conducted previously, an analysis of the state of the hospital environment at a pediatric oncology unit demonstrated the presence of CD spores on elements in direct contact with patients and on parts of doctors clothing. The study was performed using C. diff Banana Broth™ medium , which is used for culturing and recovering CD spores and vegetative cells from environmental samples. The obtained results indicate the main sources of spore transmission and the need for continuous monitoring of the situation of high-risk patients, in whom long-term contact with the hospital environment is a very significant prognostic factor for the occurrence of a CDI . In thisThe obtained results indicate that as many as 17 patients with a confirmed CDI infection have been administered antibiotics in the last 2 weeks, out of which 88% were antibiotics related to a high risk of a CD infection . Wide-spectrum antibacterial antibiotic therapy could have been the main factor determining the occurrence of CDI symptoms. In most cases, empirical treatment started after admission to the hospital was not replaced with targeted treatment. A wide bactericidal spectrum of the listed drugs results in disturbances to the natural microbiota, the selection of resistant strains, and conditions favoring the germination of CD spores. A meta-analysis by Brown and a previous study by Bartlett indicate different clinical risks of CDI occurrence for different antibiotics. Clindamycin, cephalosporins, and fluoroquinolones may constitute the greatest hazards ,35. In tThe use of general anesthesia and opiates may impair the functions of the gastrointestinal tract. In mice exposed to morphine, researchers have shown changes in intestinal epithelium and suppression of intestinal mucus . In our Our study had some significant limitations, mainly related to the COVID-19 pandemic. Due to the specifics of CD infections in pediatric population, there are difficulties in collecting a wider group at a single medical facility. The data contained in the documentation of patients often omitted significant data concerning changes in disease dynamics or attachments resulting from referral to diagnostic examinations. It should be emphasized that it was a single-center study, focusing on a single unit, with the specifics and high complexity of cases and risk factors preventing the comparison of this group of children to other patients. Our observations indicate that the course of an oncological disease may differ completely even in the case of the same type of cancer; therefore, significant heterogeneity exists within a single group. In Poland, the total number of all reported cases of CDI in children and teenagers in 2020 was 307 (in 16 provinces). In the Chief Sanitary Inspectorate reports, there is no information concerning what percentage of these are oncological patients. The dynamics of the spread of infections caused by CD require strict epidemiological control. Establishing the clinical conditions related to infections caused by CD in pediatric oncological patients becomes more and more important in the context of the medical consequences and risks resulting from the delaying of the primary treatment.The conducted study demonstrates that infections caused by toxigenic CD strains constitute a real diagnostic and therapeutic problem in pediatric patients. Antibiotic therapy is one of the main factors determining the occurrence of a CDI. A dangerous phenomenon was the lack of a noticeable change from the primary antibiotic therapy to drugs acting on a narrower antibacterial spectrum. The highest risk of CDI was associated with the use of beta-lactam antibiotics , such as amoxicillin with clavulanic acid and third-generation cephalosporins. The possibility of reducing or substituting the use of the drug should be assessed. Cases of treatment for CD without reasonable grounds should be excluded. Oncological treatment combined with additional risk factors, such as malnutrition, low neutrophil count (high risk of neutropenic fever), transfusion of blood components, assisted feeding, and protein disturbances, may, in our opinion, constitute additional CDI-related prognostic factors. Medical interventions undertaken in the process of treating an oncological disease generate consequences that may impact the occurrence of CDI. Excluding all coincidences and making unequivocal recommendations, in our opinion, requires a multi-centerstudy at pediatric oncology units.


Medical universities use their websites to teach, research, and promote a culture of health. Therefore, this study aimed to evaluate the performance of medical universities in terms of health information and education regarding COVID-19 by surveying the website of Iranian medical universities.This descriptive-analytical study was conducted in June to August 2020 on the websites of medical universities in three categories of universities . The information of this study was collected from medical universities located in the east, west, north, south and center of Iran. Data were collected according to a checklist. The checklist contained 3 sections; the first part with 8 components regarding general information of the university websites, the second part with 11 components regarding the information and news related to the coronavirus and the third part with 12 components regarding the content of personal health education and environmental health for the prevention of coronavirus. To determine the status of each website in the two areas of health information and education, websites were divided into three categories based on scores . Data were analyzed by chi-square.2 = 10.343, p = 0.006).In this study, 1118 web pages related to 48 Iranian universities of medical sciences were reviewed, where 19 were type 1 universities, 21 type 2 universities, and 8 type 3 universities. The mean scores of the websites regarding the information and news related to the coronavirus (8.54 ± 1.750) and the mean scores of the websites regarding the personal and environmental health education related to coronavirus (10.96 ± 1.148) were in a favorable and positive condition. The ranking of medical universities by type showed that the scores in the two areas of health information and education about the coronavirus were in good condition and none of the universities were in bad condition. Chi-square showed that the information status and news related to the coronavirus had a significantly positive relationship with the type of medical universities (χThe results of this study showed that type1 and type 2 and 62.5% of type 3 medical universities were in good condition in terms of total scores in the two areas of health information and education about coronavirus and none of the universities were in a bad situation. It is suggested that the website of medical universities can serve as a reliable and appropriate source of information not only for academics and students but also for the general public. Since December 2019, cases of severe respiratory infections have been reported in Wuhan, China, which were caused and termed the coronavirus or COVID-19 [Coronavirus positive cases were then rapidly reported from Thailand, Japan, South Korea and the United States throughout January 2020. Person-to-person transmission of the coronavirus and transmission to healthcare workers spread rapidly and caused a most devastating epidemy to mankind . The corAmong the various websites, the websites of medical universities are thought to be of great importance as a reliable source to conveying health news and concepts to the public . The webMedical universities use their websites to teach, research, and promote a culture of health. Since the outbreak of the coronavirus in Iran, medical universities provided information and preventive training on the capacity of their websites in various sections, such as the hospitals website and the health deputy website , 14. SinThis descriptive-analytical study was conducted in June to August 2020 on the websites of medical universities of Iran. The information of this study was collected from medical universities located in the east, west, north, south and center of Iran. In the present study, the websites of Iranian universities of medical sciences were divided into three categories . The ranking of medical universities was based on indicators such as research infrastructure, student research and ethics in medical research and indicators in the field of science production. Universities that were in good condition in terms of these indicators were ranked first (type 1), universities with average and poor status were ranked second (type 2) and third (type 3), respectively. There are 48 universities of medical sciences in Iran. For this research, we first entered the main page of the website of 48 universities. Then, for each university, we checked the website pages of the faculties, the website of the Vice Chancellor for Health and the website of the educational centers  affiliated to each university. In total, 1118 websites from 48 universities of medical sciences were reviewed , 4 to 7 (medium) and 8 to 11 (good).In the personal and environmental health education checklist, the minimum and maximum scores for each website were zero to 12. Regarding the status of the personal and environmental health education of each website, the scores obtained were reported at three levels: below 4 (poor), 5 to 8 (medium) and 9 to 12 (good).The scores of the two sections of information and news, personal and environmental health education were zero to 23 for each of the websites. The scores obtained were reported for three levels: below 7 (poor), 8 to 15 (medium) and 16 to 23 (good).Data were analyzed by SPSS software version 22, descriptive and analytical statistics. Relative frequency and percentage were used for data analysis in the descriptive statistics section, and chi-square test was used for statistical analysis. P < 0.05 was considered as statistically significant.In this study, 1118 web pages of 48 Iranian universities of medical sciences related to health departments, faculties and hospitals of Iranian universities of medical sciences. They belonged to type 1 universities , type twThe mean scores of the websites regarding the information and news related to the coronavirus were in positive condition 8.54 ± 1.750). The highest percentage was related to component 6 (Ability to search for phrases related to the coronavirus). The highest mean scores were related to components 6,4 and 5 regarding the search for terms related to coronavirus. The lowest mean score was for component 2 (linking to WHO resources and subject databases for information on coronavirus) . The highest mean scores were related to questions 3, 4, 8, 9 and 10 regarding education on personal hygiene such as using masks and gloves, disinfectants and social distancing. The lowest mean scores were related to question 7  and question 6 (food hygiene) Table .Table 2SChi-square showed that the performance of Type1 and Type2 universities in terms of information and news on the coronavirus and personal and environmental health education was better than that of Type3 medical universities. Chi-square showed that the ability to search easily for coronavirus had a significant relationship with the type of medical universities (p = 0.046). Type1 universities of medical sciences were 100%, Type2 universities of medical sciences were 95.2% and Type3 universities of medical sciences were up to 75% capable of simple search for coronavirus. In 84.2% of the websites of Type 1 universities of medical sciences, in 95.2% of the websites of Type 2 universities of medical sciences, in 50% of the websites of Type 3 universities of medical sciences, the latest news of coronavirus has been published. Chi-square showed that significant relationship between coronavirus news and type of medical universities (p = 0.014). Chi-square showed that the publication of morbidity and mortality of coronavirus on the university website was significantly related to the type of medical universities (p = 0.056) (Table The highest scores about information and news about coronavirus were related to type 2 universities (90.5%) and the lowest were related to type 3 universities (5.37%).The highest scores about personal and environmental health related to coronavirus were related to type 1 and 3 universities (100%) and the lowest were related to type 2 universities (90.5%) Table .Table 4R2 = 10.343, p = 0.006). . Therefore, based on the findings of the present study, scientific websites are a suitable tool for health education. In a study by Hamzehei et al. 2018), it was reported that reliable scientific websites such as health and medical websites can be used for health education about diseases. In a st18, it waThe mean scores of the websites regarding personal and environmental health education related to the coronavirus were favorable (10.96 ± 1.148). The highest mean scores were related to education about personal hygiene such as using masks and gloves, disinfectants and social distancing. The lowest mean scores were related to hygienic disposal of solid waste produced by coronavirus and food hygiene. In a study by Zarghani et al. (2017) with the aim of determining the services provided on the website of the central libraries of medical universities showed that 77.8% of the websites offered "library usage training" . In receType1 and Type2 universities (100%) and Type3 62.5%) of medical universities showed good conditions in terms of total scores in the two areas of health information and education about the coronavirus, and none of the universities were in bad conditions. In a study by Hamidi et al. (2016) with the aim of evaluating the websites of Iranian universities of medical sciences in terms of attention to content and technical characteristics showed that type one and type two universities were better and type three universities had the lowest levels of compliance 2.5% of m. The resThe results of this study showed that type1, type2 and 62.5% of type3 medical universities were in good conditions in terms of total scores in the two areas of health information and education about coronavirus and none of the universities was actually in an unacceptable situation. The use of cyberspace and websites have benefits such as increased awareness without having to leave home in the prevalence of coronavirus. Other benefits include easy information access, increasing attention and usefulness of information, high speed of information dissemination, access to information at low cost. Therefore, it is suggested that the website of medical universities should be introduced as a reliable and appropriate source to the general public.To maintain a permanent page for health education on infectious diseases such as the coronavirus that shall be available from the main website of medical universities.Web-based databases should be created for information about academic and research resources related to coronavirus available for a wide public.According to the results of the evaluation of websites, it is suggested:


We report on the experimental investigation of the ultrafast dynamics of valley-polarized excitons in monolayer WSe Valleytronics in transition metal dichalcogenide monolayers 2D TMDs) has become a widely studied topic aiming for the development of a new type of electronics, in which the role of electron charge is replaced by a new quantum number associated with the specific band structure extrema occupied by an exciton D TMDs ha,4,5,6,7.Here, we study the valley polarization of excitons in monolayered WSeThe ultrafast dynamics of valley polarization of excitons in monolayer cross in  with twoThe WSe crystal ,28. The  eV (see ) and by t after the excitation The measured dynamics of transient reflectivity spectra The measurements are performed for co-rotating circular polarizations of the pump and probe pulses labeled as We observe an increase in reflectivity in the spectral region from 1.61 to 1.67 eV after the arrival of the pump pulse, which is present for both combinations of circular polarizations. This increase in reflectivity corresponds to absorption bleaching of the 1sA exciton resonance with the transition energy of 1.639 eV ,32 due tThe dynamics of the transient reflectivity change integrated over the spectral region of 1.61–1.67 eV for both combinations of circular polarizations is shown in In the transient reflectivity data shown in the upper panel of To study the dynamics of valley polarization of excitons, we subtract the transient reflectivity dynamics of the exciton resonance measured with a counter-rotating combination of circular polarizations from the data with a co-rotating combination. The resulting dynamics of valley polarization are plotted in The different dependence of the two dynamics on the fluence of the pump beam points out their different physical origins. The initial fast decay dynamics, which does not depend on pump fluence, is probably related to the time in which the excitonic system relaxes and loses the excess energy, which is a consequence of the broad spectrum of the excitation (up to 1.9 eV). However, the spectrum does not reach the band gap of the material of 2.05 eV and we thus do not expect excitation of free electrons and holes but rather the direct excitation of the 1sA exciton states. Even with above band gap excitation, the excitons are formed within the first few tens of femtoseconds after the excitation  due to tn–phonon  and excin–phonon ,38 intereraction ,39. We action  . For theThe characteristic time of the scattering processes strongly depends on the type of scattering. Using the expression for the second term in the equation of motion, this time can be estimated as a full escaping time of the exciton from the state /ℏ) (see  for detaeter A∼1 ,52,53,54orted in ,38,55. ITherefore, we restrict ourselves to the qualitative analysis of the processes presented in the Maialle–Silva–Sham equation. The application of the strong pump pulse generates excitons in Klley see . FinallyIn summary, we show that the excitonic valley polarization dynamics in monolayer WSe