Vertical jump performance was determined by counter movement jump (CMJ) and counter movement jump with free arms (CMJFA) tests. A running-based anaerobic sprint test (RAST) determined the relative power output (watts/kg body weight) and absolute power output (watts) of the players. Sprint performance over 5 m, 10 m, and 30 m distances was evaluated. An incremental shuttle run test (40 m) was designed to determine aerobic threshold (AeT), anaerobic threshold (AnT), and [LA]peak. All parameters were measured for pivots, wingers, backs, and goalkeepers of each group. The U19 players were significantly heavier than the U17 group, but both the groups were nearly equal in height. The U19 group jumped higher than the U17 members, although the only significant difference (p = 0.032) was observed between the wingers of the groups in CMJ. Sprint performance varied marginally between the groups and only U19 pivots were found to be significantly  faster than U17 pivots. No difference in relative power output between the groups was noted, although the U19 players recorded higher absolute power outputs. Maximal velocity and velocities at the AeT and AnT were almost similar in the groups. Distance covered by the groups at the intensities of AeT and AnT varied only little. Higher [LA]peak was observed in the U19 players. U19 players failed to convert their superior power into speed and jump. The training pattern of the handball players needs to be revised so that U19 players may develop faster and be more enduring than the U17 group.This study evaluates the anatomical profiles, jump, sprint, power outputs, endurance, and peak blood lactate levels ([LA] Selection and training systems of sports schools in Poland, coordinated by various sports bodies, including the Polish Handball Federation, have merits and demerits. Besides providing sports training to their athletes, sports schools in Poland focus on other social matters as well. The assessment of a player’s talent in team sports is based on three areas: motor skills and physique, mental health, and social features ,2,3. A cHandball players require specific training that allows them to perform cyclic and acyclic activities efficiently during 60 min of match play. Like many other team sports, the movement pattern of handball players during match play is intermittent, intense, and varies widely in phases of defense and attack ,8. Apart2max and at a blood lactate concentration of 3 to 11 mmol/L. The VO2max of the youth (16–21 year) handball players varies from 50 to 65 mL/kg/min, which partly depends on their position of play. The blood lactate concentration in same group of handball players after a run ramp test for the exhaustion is 10–12 mmol/L  recorded following the end of the test was recorded as the [LA]peak.Peak blood lactate concentration ([LA]Determination of aerobic threshold (AeT): the running intensity at which the [LA] increased by 0.5 mmol/L was marked as the AeT .Determination of anaerobic threshold (AnT): the running speed at the [LA] of 4 mmol/L was considered as the AnT of the player . The total distance of run, completed by the subject in the endurance test, was divided into three intensity zones—(a) zone 1: up to AeT, (b) zone 2: above AeT to AnT, and (c) zone 3: above the AnT level.p ≤ 0.05. All calculations were performed with STATISTICA ver. 13.3 .Mean and standard deviation were used to represent the average and the typical spread of values of all the measured variables. The normal Gaussian distribution of the data was verified by the Shapiro–Wilk’s test. If the data were normally distributed within groups, an independent samples t-test was used to test the differences between U17 and U19. If the data were not normally distributed, a Mann–Whitney U-test was used. Two separate one-way analyses of variance with a Tukey post-hoc test were used to determine whether and where differences existed in the all measured variables between the playing positions in each age group. The effect size (ES) of the intervention was calculated using Cohen’s guidelines. Threshold values for ES were >0.2 , >0.6 (moderate), >1.2 (large), and >2.0 (very large) . StatistBody weight and height of the U17 and U19 players are presented in p-values and the ES of the difference, are presented in Sprint performance (time) of the participant handball players, for various distance marks, as well as differences in performance between U17 and U19 groups, and the max), minimum power (Pmin), average power (Pav), and fatigue index (FI), recorded in RAST, are presented in max, Pmin, and Pav—of U19 outfield players exceeded the power outputs of U17 players of similar positions, although the difference in none of the cases was found to be significant. Only goalkeepers of the U17 group demonstrated higher Pmin and Pav than the U19 goalkeepers, although the ES was only trivial. Wingers of both the U19 and U17 groups showed higher Pmax and Pav than other players of their own group. No significant difference of FI between the groups was found and the ES varied from trivial to moderate.Maximum power  of the older age group (U19) were recorded higher than those of the younger group (U17) of handball players and the difference was significant in all the cases, except Pmin between the goalkeepers. The ES varied from moderate to large.max), velocity at the aerobic threshold (VAeT), and the velocity of the players at the intensity of anaerobic threshold (VAnT), determined in endurance test, are presented in max, VAeT, and VAnT. When compared between the age groups (U19 and U17), the difference of the velocity for any given intensity was only marginal, no significant difference was observed in any of the cases, and the ES varied only from trivial to small.Maximum velocity (VTOTAL) is the arithmetic sum of the distance covered up to the aerobic threshold (DAeT) and the distance covered up to the intensity of anaerobic threshold (DAnT) (but higher than the AeT level). Like velocity, the difference of distance covered for any of the three given intensities between the groups (U19 and U17) was marginal again. Only DTOTAL of the U19 backs was found to be significantly higher than that of the U17 backs.The distance covered by the players at three different intensity zones is shown in max% at the intensities of AeT (HRAeT) and AnT (HRAnT) of the participants. No significant difference in HRAeT and HRAnT between the age groups was found, except the HRAeT of the backs.peak of the subjects recorded after the end of the endurance test. The players of all the positions of U19 demonstrated higher [LA]peak than their U17 counterparts, although the difference was statistically significant only between the backs (p < 0.001) and the pivots (p = 0.037) of the two groups.Handball players need specific training that allows them to do multiple and complex physical tasks successfully. Like many other team sports, age, training, skill, and playing position serve important roles in developing efficiency in handball players ,44. The Pivots experience more physical confrontations than players of any other positions, against the opponent team members, during a game. As a result, strength and explosive power are some of the primary requirements for pivots ,29. ThisTraining of high intensity and long duration act as appropriate stimuli that favor to improve or maintain body stature and power . Raspberpeak of the pivots of U19s was ~23% higher than that of the younger (U17) group of players. However, the Vmax, VAeT and VAnT of the U19 pivots were only marginally higher than those of the pivots of the U17 group.In case of the pivots, the anaerobic power generated was largely transferred to external loads, as noted by Krüger et al. . This isp < 0.001; ES = very large) in the higher age group (U19). With a significant increase in body weight, a significant increase in anaerobic power and explosive strength is expected in U19 wingers compared with their U17 counterparts. However, an increase in muscle mass in U19, if any, and its role in the improvement of explosive strength requires further study. In the studied groups, no significant difference in speed over the distance of 5 to 10 m was found. The difference in explosive power is clearly visible in the CMJ results (p = 0.032) between the two age groups. The height of CMJ is higher by 11% and CMJFA by 9% in the U19 group. Thus, the increase in mass is accompanied by an increase in explosive power, but the increase in muscle mass did not support faster running in the U19 players. This observation is also supported by the fact that the absolute power (watts) output in the U19 players in RAST was significantly higher than that in the U17 group, but no such difference existed when the power was expressed in watts/kg body weight. While an increase in muscle mass is usually associated with an increase in power, there is no real difference in power with respect to the body mass in both age groups in this study. Improper training methods and loads probably failed to stimulate the relative increase in power in U19 players  than the participants of the U17 group. This suggests a decrease in the running economy in the U19 group compared with the U17 group . The relpeak, in spite of lower HRAeT in comparison with the U17 backs. The strength training is likely to improve the sprint, acceleration, and jumping and throwing abilities of the handball players. The longer distance covered by the backs during competitive match play needs reasonable aerobic training as well  as well ,63. A sie groups . In backBesides game-specific skill, handball goalkeepers are trained for developing explosive power, which is a prerequisite to efficient and effective jumping, throwing the ball, and quick acceleration of movement in all possible directions ,27,32.Total and DAeT by the U19 participants indicate higher aerobic capacity in U19 handball players than U17 players. More intense and frequent anaerobic training stimulated the anaerobic glycolytic system in the older group (U19) of handball players, and this was reflected by higher [LA]peak in these players than the U17 participants. The reason for the limitations of the motor development of goalkeepers of U19 may be slowing down of biological maturity after 17 years of age [The height of the goalkeepers of both the age groups, like outfield players, does not vary significantly . Howevers of age .The aim of this cross-sectional study was to compare physical fitness and some physiological characteristics of U17 and U19 Polish handball players with special reference to their position of play. Players of both the groups were equally taller, but the U19 members were significantly heavier than the U17 participants. Players of all the U19 positions dominate over the U17 players in terms of absolute power. However, a higher body weight has eliminated these differences in relative power values. Increases in body weight and total muscle mass in U19 players were responsible for superior explosive power, which caused better performance in the jump tests (CMJ and CMJFA) when compared with U17 players. The players of the U19 group showed lower running efficiency up to AeT level and longer distance covered above AeT than the U17 group. However, the U19 players possessed higher anaerobic capacity and an efficient glycolytic system compared with the group of U17 players. Players with higher body weight (U19) worked at a significantly higher energy cost level compared with the players of lower body weight (U17) of similar playing positions.The research has limitations on its wide use in men’s handball. The training system in a sports school has strict conditions that are different from training in sports clubs. The sports school players who participated in the research did not differ in the organization of the day, diet, and training loads. When relating the results of the presented studies to the values obtained in other training groups, the above limitations, which constitute an integral part of each sports training process, should be taken into account.Training of U19 groups should be targeted to transfer power into speed. There is a clear increase in maximum power with a lack of adequate development of running speed at distances important in handball (5 and 10 m). This is because of the fact that weight gain is not accompanied by an increase in relative power, so the observed power development is only compensated for by weight gain. It is also important because of the size of players, which limits their flexibility and ability to change directions rapidly. Development of endurance and running economy of the players should not be ignored, while focusing the training on the explosive power and sprinting ability of the players. It is recommended to increase the training impact at the age of 17–19 towards the development of running economy and speed increase on the thresholds (AeT and AnT).


To evaluate liver lesions, in accordance with the LI-RADS classification, using contrast-enhanced multiphase dynamic computed tomography in patients with hepatitis B, coinfected or not with hepatitis D, or with chronic hepatitis C, as well as to determine the level of agreement between radiologists.We evaluated 38 patients with hepatitis B, coinfected or not with hepatitis D, or with chronic hepatitis C, all of whom underwent contrast-enhanced multiphase dynamic computed tomography. For each examination, two radiologists selected up to three hepatic lesions, categorizing them in accordance with the LI-RADS classification and evaluating signs of chronic liver disease and portal hypertension. To determine the level of agreement between radiologists, we calculated the kappa statistic (κ) .Radiologist 1 and radiologist 2 selected 56 and 48 liver lesions, respectively. According to radiologist 1 and radiologist 2, respectively, 27 (71%) and 23 (61%) of the 38 patients had at least one liver lesion; 13 (34%) and 12 (32%) had a LI-RADS 5 lesion (κ = 0.821); 19 (50%) and 16 (42%) had a hypervascular lesion (κ = 0.668); and 30 (79%) and 24 (63%) had splenomegaly (κ = 0.503). Both radiologists identified chronic liver disease in 31 (82%) of the patients (κ = 1.00).Lesions categorized as LI-RADS 5 were detected in approximately 32% of the patients, with almost perfect agreement between the radiologists. The level of agreement was substantial or moderate for the other LI-RADS categories. The main risk factors for HCC are infection with the hepatitis B virus (HBV) and liver cirrhosis, which is present in up to 90% of patients with HCC,4. The main causes of hepatic cirrhosis are chronic viral hepatitis caused by infection with the hepatitis B virus or the hepatitis C virus , alcoholic cirrhosis, and nonalcoholic fatty liver disease. It is known that HBV is carcinogenic and can lead to the development of HCC even in the absence of cirrhosis.In Brazil, the estimated incidence of hepatocellular carcinoma (HCC) in 2016 was 10,000 cases, with a crude mortality rate of 5.1/100,000 population, making it the sixth leading cause of cancer-related death in the country.For individuals in the population groups at risk of developing HCC, it is common to undergo abdominal ultrasound screening every six months either with or without determination of the alpha-fetoprotein level. When a focal lesion ≥ 1 cm is identified in the abdominal ultrasound screening, the use of a cross-sectional imaging method, such as contrast-enhanced multiphase dynamic computed tomography (CT) or magnetic resonance imaging (MRI), is indicated in order to confirm the diagnosis and staging-12, in order to standardize the descriptions of hepatic lesions in cirrhosis among radiologists and to facilitate communication within multidisciplinary groups.In 2008, the American College of Radiology created a system of data and reports known as the Liver Imaging Reporting and Data System (LI-RADS), which has high specificity for the diagnosis of HCCIn the present study, we evaluated the hepatic lesions identified by contrast-enhanced multiphase dynamic CT in accordance with the LI-RADS classification in patients with chronic HCV or with HBV, coinfected or not with the hepatitis delta virus (HDV), and looked for signs of chronic liver disease. We also gauged the level of interobserver agreement.This was an analytical, cross-sectional, observational study, involving a convenience sample of 38 patients with chronic hepatitis C or with hepatitis B, coinfected or not with HDV, treated as inpatients or outpatients at Hospital das Clínicas de Rio Branco, in the state of Acre (in northwest Brazil), between April and December of 2017. All of the patients underwent contrast-enhanced multiphase dynamic CT. Epidemiological data were collected by interview on the day of the examination or from medical records. Pregnant women were excluded from the study, as were patients younger than 18 years of age and patients with contraindication to the contrast medium. The study was approved by the local research ethics committee (Reference no. 58423116.2.0000.5010)., with a slice thickness of 1.5 mm. We used nonionic iodinated contrast  at a dose of 1.2 mL/kg, administered by injection pump at a rate of 3.0 mL/s, and a control tool to trigger the contrast for acquiring the contrast-enhanced images in the arterial, portal, and equilibrium phases. The acquisition control of the arterial phase was based on a density of 180 HU measured in the region of interest located in the transition from the thoracic aorta to the abdominal aorta. The portal phase and equilibrium phase images were acquired at 40 s and 180 s, respectively, after the end of the arterial phase.The CT scans were acquired in a 16-slice multidetector scanner  and the protocol followed was that for the upper abdomen with helical acquisitions before and after administration of intravenous contrast medium with a dynamic study, in accordance with the American College of Radiology recommendations for application of the LI-RADS 2018 versionThe imaging findings of the liver were analyzed by two radiologists , working independently, who classified the hepatic lesions, referred to as hepatic observations in the present study, according to the criteria established in the LI-RADS version 2018. Signs of portal hypertension, hepatomegaly, collateral circulation, ascites, splenomegaly, and chronic liver disease were also evaluated..The qualitative criteria used in considering signs of chronic liver disease were widened fissures, heterogeneity of the parenchyma, and irregular contours . Advance. Splenomegaly was identified by determining the splenic index , which has an upper limit of normality of 480.Hepatomegaly was defined as the left lobe of the liver measuring > 6 cm along its longest (anteroposterior) axis and the right lobe measuring > 16 cm along its longest  axisUp to three hepatic observations were selected from each examination , categorized in descending order from the largest in the highest LI-RADS category to the smallest in the lowest. The lesions were evaluated for the presence of the major HCC criteria: hypervascularity, washout, and pseudocapsule . Each ra: perfect (κ = 1); almost perfect ; substantial ; moderate ; fair ; and slight .The data collected were analyzed with the IBM SPSS Statistics software package, version 20.0 . The kappa statistic (κ) was calculated to assess the level of agreement between the imaging findings and the LI-RADS categories. The level of agreement was categorized, in accordance with the kappa statistic, as follows: 0.00 < r < 0.30 (weak); 0.30 ≤ r < 0.60 (moderate); 0.60 ≤ r < 0.90 (strong); and 0.90 ≤ r < 1.00 (very strong).To evaluate the level of agreement for the observation 1 measurements, splenic index, measurements of the right hepatic lobe, and measurements of the left hepatic lobe, we used Pearson’s correlation coefficient (r). For the value of r (strength of the linear correlation), we considered the following categories, which classifies the severity of chronic liver disease on the basis of biochemical values  and clinical findings , the score ranging from 1 to 3 for each item. For each patient, the disease was categorized as Child-Pugh class A (5-6 points), B (7-9 points), or C (10-15 points), a lower score indicating a better prognosis.For the clinical evaluation of patients, we employed the Child-Pugh scoring systemThe study included 38 patients, 25 (66%) of whom were male. Ages ranged from 19 to 75 years . All 38 patients had viral hepatitis: 12 (32%) had HBV only; 11 (29%) were coinfected with HBV and HDV; 11 (29%) had chronic HCV only; one (3%) was coinfected with HBV and HCV; and one (3%) was coinfected with HBV, HCV, and HDV. Overall, 25 (66%) of the patients had HBV and 13 (34%) had chronic HCV.It was possible to calculate the Child-Pugh score in 14 patients, among whom the disease was categorized as Child-Pugh class A in 11 (79%) and as Child-Pugh class B in 3 (21%). For the remaining patients, the examinations did not yield enough information to calculate the Child-Pugh score.The most frequent common findings were signs of chronic liver disease  and splenomegaly . Therefore, there was perfect agreement in identifying the signs of chronic liver disease .We selected 56 observations made by radiologist 1 and 48 observations made by radiologist 2. At least one liver lesion was detected (observation was made) by radiologist 1 and radiologist 2 in 71% and 60% of the patients, respectively. There was substantial agreement on the location of the majority of the lesions (κ = 0.723), most of which were found in the right lobe. Of the patients in whom there were no focal hepatic observations, 71% were categorized as having Child-Pugh class A disease.p = 0.721). Radiologist 1 categorized 13 (48%) of the 27 observation 1 lesions as LI-RADS 5, whereas radiologist 2 categorized 12 (52%) of the 23 observation 1 lesions as LI-RADS 5. Therefore, the interobserver agreement for LI-RADS 5 lesions was almost perfect (κ = 0.821).Radiologist 1 identified 27 hepatic lesions and radiologist 2 identified 23, all considered observation 1 lesions, with substantial agreement regarding the LI-RADS classification  of the 38 examinations. Of those 11 lesions, 6 (55%) and 3 (27%) were < 2 cm and < 1 cm, respectively. In addition, 4 (36%) of those 11 lesions were categorized as LI-RADS 3 by radiologist 1 and were not identified by radiologist 2. All four of those lesions were hypervascular, probably representing perfusion disorders. Three patients presented observation 2 lesions meeting the LI-RADS 5 criteria, with substantial agreement between the two radiologists in relation to the classification of the categories of those observations (κ = 0.658), as can be seen in In relation to the major criteria identified in observation 1 lesions, the two radiologists collectively identified hypervascular lesions in 70% of the observations selected and evaluated  who underwent CT. We found that approximately 32% of the patients presented with LI-RADS 5 observations . We also observed substantial to moderate agreement between the two evaluators in terms of the LI-RADS categories. These findings demonstrate not only how important it is for reports to be systematized for diagnosing HCC but also how important it is to have good communication within a multidisciplinary team.Recent studies in the radiology literature of Brazil have emphasized the importance of imaging examinations in the evaluation of hepatic neoplasms showed slight to moderate interobserver agreement for categorizing hepatic lesions by means of the LI-RADS. That discrepancy can be explained by the superior training and practice with the LI-RADS classification on the part of the radiologists, as well as by the smaller number of radiologists involved, in the present study. The selection of higher categories (LI-RADS 4 and LI-RADS 5) could also explain the higher levels of agreement observed in our study. Our findings are similar to those of Zhang et al., who also used a smaller number of radiologists and found no statistically significant difference between two groups of readers in terms of the LI-RADS categories. Greater experience with the LI-RADS classification on the part of the radiologists is important for greater interobserver agreement.Because the LI-RADS classification system is recent, there have been only a few studies using the LI-RADS with verification of the interobserver agreement. Unlike our findings, those obtained by Barth et al., as has occurred with other well-established classification systems, such as the Breast Imaging Reporting and Data System,25. It has been shown that training and experience in applying the Breast Imaging Reporting and Data System improved the level of agreement and the performance of radiologists. Studies have indicated the need to refine and reduce the complexity of the LI-RADS classification, which will only be possible if it is more widely disseminated. It is expected that the routine use of this classification system will improve the level of agreement and the performance of radiologists. The LI-RADS classification should be used on a routine basis by radiologists, with a learning curve and accumulation of experience,24. In one of those studies, using MRI, the association between the dimensions of the lesion and the level of interobserver agreement for the LI-RADS categories was evaluated and the authors found no difference in the assessment of major and minor lesions. The use of MRI, which is suited to tissue characterization, can explain the difference in results. The LI-RADS 3 category presents intermediate probability of HCC. The observations that are too mild to meet the criteria for LI-RADS 2 (probably benign) and too severe to meet the criteria for LI-RADS 4 (probably HCC) are classified as LI-RADS 3. Therefore, when the diagnosis is questionable, there is also a tendency towards choosing the category with a lower degree of certainty . Therefore LI-RADS 3 lesions will always be the ones for which there is the most diagnostic uncertainty , among which the LI-RADS 3 category was more common, the level of agreement fell from substantial to moderate. Two other studies also reported greater difficulty in characterizing LI-RADS 3 lesionsertainty . and Bashir et al., both of whom reported moderate interobserver agreement for the major LI-RADS criteria and for the classification of observations, as well as reporting excellent agreement for the measurements of the lesions when comparing hypervascular lesions on CT and MRI in patients at risk for HCC. Although we identified a strong correlation between the dimensions of the lesions and the level of interobserver agreement, it was weaker than that described by Barth et al. and Bashir et al.-both of whom used information from MRI-a method that is more accurate and more suited to tissue characterization, which facilitates the delimitation of the lesions and may explain the difference in correlation when compared to our work. Despite CT being less suited to tissue characterization than is MRI, it is also effective in the diagnosis of HCC, including the infiltrative type, a lesion that is more difficult to delimit, as was also observed among our patients with HBV/HDV coinfection, in the state of Acre, and may have hindered the measurement of the lesions by the radiologists in our study.The present study reports that interobserver agreement was substantial for the identification of hypervascular observations and moderate for the identification of washout and a pseudocapsule (major criteria). We also found a strong correlation between the dimensions of the lesions and the level of interobserver agreement. Our findings are in agreement with those of Barth et al.,4. It is worth mentioning that the radiological signs of chronic liver disease are not clearly revealed in its initial phase, at which time the liver may still have a normal morphological aspect, but are evident in its later stages, which could explain the high level of interobserver agreement for its diagnosis.In the present study, hepatic cirrhosis was the most common imaging finding identified by radiologists, who were in perfect agreement for this aspect. It is known that hepatic cirrhosis is an important risk factor for HCC-31, was the second most common imaging finding in the present study, and the level of agreement was only moderate, even with the use of the splenic index. Measurements along the longer axes of the spleen in different planes could explain the different interpretations. It should be emphasized that splenomegaly is one of the findings that characterize portal hypertension, and it has been associated with a worse prognosis.Splenomegaly, which is common in patients with portal hypertension-34. It is believed that the high frequency of hepatitis B reflect failures in vaccination campaigns in that region. The hepatocarcinogenic effect of these hepatitis viruses is well known,36, including the increased risk of HCC in cases of coinfection,37. In our study, the frequency of LI-RADS 5 lesions was greater in the patients with hepatitis B, although that might have just been due to the larger number of individuals infected with the virus in the sample.One peculiarity of our study in relation to others that used the LI-RADS classification was the presence of patients infected with HDV . We believe that the high rate of HBV/HDV coinfection was related to the study population, because the rate of HBV/HDV coinfection is high in Acre. The patient selection process might also have played a role, because the study was conducted at a referral center for infectious diseases, which in itself could lead to overestimation of the coinfection rate. Studies have shown a high prevalence of the HDV in the population of the western Brazilian Amazon, which includes the state of Acre  and the state of Amazonas, the two states in which the patients in our sample residedOne of the limitations of our study is that we used CT rather than MRI for the evaluation of hepatic lesions. We chose to use CT because MRI is an expensive imaging method and not widely available in the northern region of Brazil. A limitation inherent to the use of CT is its inability to evaluate the ancillary features addressed in the 2018 version of the LI-RADS. In addition, the small sample size precluded the analysis of a possible correlation between LI-RADS 5 lesions and HBV/HDV coinfection.In conclusion, the level of interobserver agreement between our two radiologists was substantial to moderate for the classification of the observations into LI-RADS categories and almost perfect for the presence or absence of a LI-RADS 5 lesion. Our findings suggest that the LI-RADS classification can be an important tool for the diagnosis of classic HCC, which is treatable without biopsy, and can improve the analysis of and diagnosis based on these imaging findings by standardizing radiology reports and improving understanding by the multidisciplinary team.


The purpose of this study is to conduct a comparative analysis of the consumption of antibiotics for systemic use reimbursed by the state in Kazakhstan for 2017–2019 with the Access, Watch, and Reserve classification (AWaRe 2019) of the World Health Organization (WHO). The evaluation of the consumption of antibiotics for systemic use in Kazakhstan for 2017–2019 was carried out using the ATC/DDD methodology in accordance with the WHO AWaRe classification. The study used data on all antibiotics that were centrally purchased by a single purchaser during the study period. To understand how often Access group antibiotics are taken in Kazakhstan, the top-10 most consumed antibiotics were additionally studied. The results of a comparative analysis of the antibiotics for systemic use consumption for 2017–2019 by the Access, Watch, and Reserve groups showed a negative trend of a decrease in the consumption of Access group drugs from 1.17 defined daily dose (DDDs) per 1000 inhabitants per day (DID) (39%) in 2017 to 0.59 DID (30%) in 2019. There is an increase in consumption of Watch group antibiotics from 1.84 DID (61%) in 2017 to 1.37 DID (68%) in 2019, as well as an increase in consumption of Reserve antibiotics from 0.001 DID (0.03%) to 0.4 DID (2.11%). In recent years in Kazakhstan, there has been a decrease in the consumption of Access group antibiotics. In addition, the Watch group antibiotics are widely consumed with a certain upward trend. In 2019, one Reserve antibiotic was included in the top-10 most commonly consumed antibiotics. There is a predominant consumption of parenteral forms of antibiotics for systemic use in the country. Antimicrobial resistance (AMR) is a global problem of public healthcare that comes with huge social and economic losses due to infectious diseases. The potential for widespread use of antimicrobials in medical practice could lead to long-term increases in AMR mortality rates.To optimize the rational use of antibiotics and support monitoring, in March 2017, the WHO introduced a detailed classification of antibiotics, which was designated Access, Watch, and Reserve . In 2019Kazakhstan, as part of the global community, adheres to the WHO recommendations. However, despite a slight decrease in the consumption of antimicrobials for systemic use in recent years, there is still an irrational use of antibiotics in Kazakhstan. This is due to their nonprescription (27.5% of antibiotics are taken without a doctor’s prescription) and excessive prescription  leads to an increase in AMR ). In addUntil now, in Kazakhstan, single pharmacoepidemiological studies have been carried out to determine the effectiveness and safety of the use of drugs at the population level. Even though in recent years, extensive activities have been carried out to raise awareness of the population and medical workers, the problem of irrational consumption of antibiotics is still a complex issue of national health care. The main volume of medical care provided to the population of Kazakhstan is reimbursed by either the state or the social health insurance fund. Therefore, the study of the consumption of antimicrobial drugs in the country’s public medical institutions will make it possible to assess the real picture and develop effective measures to contain antimicrobial resistance.This study aims to conduct a comparative analysis of the consumption of antimicrobials for systemic use reimbursed by the state in Kazakhstan for 2017–2019 with the WHO AWaRe classification.The results of the evaluation of antibiotic consumption for systemic use showed a decrease in total antibiotic consumption from 3.03 DID in 2017 to 2.66 DID in 2018 and 2.00 DID in 2019. Along with this, there was a decrease in the proportion of consumption of oral forms of antibiotics from 48.6% and 46.8% in 2017 and 2018 to an average of 9.2% in 2019 (38.5%), and when comparing 2017 and 2019, a decrease to 10.1%.The antibiotics of the group “J01D Other Beta-lactam antibacterials” lead in terms of consumption share in 2019, accounting for 50% (1.01 DID) of total consumption, followed in descending order, groups “J01M Quinolone antibacterials”, “J01F Macrolides, Lincosamides, and Streptogramins” and “J01G Aminoglycosides”, with a 30% (0.59 DID), 10% (0.2) and 7% (0.15) consumption share respectively.More detailed analysis of the “J01D Other beta-lactam antibacterials” preparation group showed that cephalosporins generations I and III took a leading position in terms of consumption in 2019, which was 43.6% and 45.6%, respectively, and 8.5% and 0.8% for generations II and IV, followed by carbapenems . Levofloxacin takes the first place among the drugs of the J01M Quinolone antibacterials group, the share of consumption of which is 74.1%.An analysis of the consumption dynamics of group “J01C Beta-lactam antibiotics, penicillins” revealed a significant increase in consumption of subgroup “J01CR02 Amoxicillin and beta-lactamase inhibitor” in 2019, while the drug Amoxicillin was not procured.One hundred and seventy-two positions of the 180 antimicrobial drugs according to the WHO AWaRe-2019 antibiotic classification are from the group of antibiotics for systemic use J01; 8 of these positions had other ATC codes: A07AA09, A07AA11, P01AB01 and 5 were “to be assigned”. This includes a total of 75 antibiotics in the EML WHO for 2019, of which 71 are for systemic use. In Kazakhstan, during the period from 2017 to 2019, only 35 state reimbursable antibiotics for systemic use reimbursed by the state were consumed.In 2017 and 2018, the pattern of antibiotic consumption did not change. The list of the Single Purchaser of Kazakhstan included 34 antibiotics for systemic use J01, including 21 items from the WHO EML list. Thirty-three out of 34 antibiotics are included in the WHO AWaRe classification of antibiotics , and 1 drug (Cefoperazone and Sulbactam) is included in the WHO non-recommended list.In 2019, the number of consumed antibiotics decreased to 29; 17 of which are included in the WHO EML. Among the 29 preparations, six were Access, 21 were Watch, and two were from the Reserve group (Fosfomycin (IV)) and Linezolid) .Twenty-two antibiotics out of all 34 included in the WHO AWaRe classification are included in the WHO EML , and 12 are not included in the WHO EML . The comparison results are presented in A comparative analysis of antibiotic consumption for systemic use in 2017–2019 by Access, Watch, and Reserve groups shows a negative trend of decreasing consumption of drugs from the Access group from 1.17 DID (39%) in 2017 to 0.59 DID (30%) in 2019. There is an increase in consumption of Watch group antibiotics from 1.84 DID (61%) in 2017 to 1.37 DID (68%) in 2019, as well as an increase in the consumption of Reserve antibiotics from 0.001 DID (0.03%) to 0.4 DID (2.11%). At the same time, in 2017 and 2018, in the list of a Single Purchaser, there was one combined antibiotic included in the WHO list of antibiotics that is not recommended for consumption .Going forward we checked the compliance with the WHO recommendations for the indicator level of the use of the Access group antibiotics—at least 60% for 3 years (2017–2019) and received the following results: in 2017 the indicator level was 39%, and it was 35% in 2018 and 30% in 2019 . TherefoIn order to understand how often Access antibiotics are used in Kazakhstan we looked at the top 10 of the most consumed antibiotics. The results of determining the indicator of antibiotic consumption at the country level according to the top 10 showed a decrease in the share of use of Access group antibiotics by almost 2 times in 2018, which amounted to 15.5% compared to 2017—33%, and there was a reverse increase in 2019 to 29.6%. The obtained results are presented in At the same time, most of the top 10 parenteral and oral antibiotics in 2019 were Watch group drugs with a share of the total consumption of 66.1%, which is 13.1% less than 2018 (79.2%) and 4.5% more than 2017 (61.6%) .In general, over the period under review, we identified a negative trend in the consumption of systemic antibiotics in Kazakhstan in all three categories of the WHO AWaRe classification. Despite a positive systematic decrease in the total consumption of antibiotics from 3.03 DID in 2017 to 2.66 DID in 2018 and 2.00 DID in 2019, there is a negative decrease in the share of consumption of oral forms of antibiotics by 10.1% in 2019, which amounted to 38.5% of the total consumption compared to 2017 (48.6%).In addition, in 2019, there is a stable leading position of antibiotics of the group “J01D Other beta-lactam antibacterial drugs”, with a consumption share of 50% (1.01 DID) of total consumption, among which the most consumed were cephalosporins of the third generation with a consumption share within the group of 45.6%. At the same time, according to the WHO AWaRe classification, 94% (17 out of 18) of generation III cephalosporins belong to the Watch group, which indicates the irrationality of the structure of consumption of antibiotics for systemic use.Analysis of overall antibiotic consumption compliance with WHO guidelines over the study period showed a systematic decrease in the consumption of Access antibiotics from 39% in 2017 to 35% in 2018, reaching 30% in 2019.More than half of the prescribed antibiotics in Kazakhstan were from the Watch group. Over the period studied, we found such a negative trend that the share of consumed Watch group antibiotics increased from 61.6% 2017) to 66.1% (2019). For comparison, in one of England’s clinics, the share of consumption of Access group antibiotics was 60.9% in 2016, and Watch was 37.9% [ to 66.1%Meanwhile, the use of Access group antibiotics among the most commonly used top 10 antibiotics varied over the study period and declined sharply from 33% 2017) to 15.5% in 2018 and increased again to 29.6% in 2019. However, the WHO recommended indicator level of at least 60% use of Access antibiotics was not achieved [017 to 15In the available literature, there were interesting results of a comparative analysis of data from 70 countries of the world with middle and high income on the use of oral forms of antibiotics in children based on WHO AWaRe in 2015 . AccordiIn 2019, Linezolid, which belongs to the Reserve antibiotics group according to the WHO AWaRe classification, entered the top 10 most consumed oral antibacterial drugs, with a consumption share of 2.1%, which poses a threat to the development of resistance to reserve drugs that should be prescribed under strict control and reporting on the reasonableness of the prescription. For comparison, in Italy, the daily consumption of “reserve” antibiotics is 2.11% of the total. This is four times the number in Germany and six times the rate in the UK, where the daily antibiotic consumption of last resort is 0.3% [If the same antibiotic has both forms  and the possibility of use, the most appropriate is the use of oral forms of antibiotics . The pre(1)lack of skills and knowledge of the prescriber;(2)improper unethical promotion of medicines by pharmaceutical companies;(3)unlimited availability of medicines;(4)profit from the sale of drugs;(5)drugs that are not affordable;(6)excessive workload of medical personnel;(7)lack of a coordinated national pharmaceutical policy .According to WHO estimation, there are seven factors promoting irrational antibiotics use:Based on this, we believe that one of the main reasons for the inappropriate use of antibiotics in Kazakhstan is the lack of guidance on antibiotic use at the national level and a lack of human resources. In total, 59% of medical institutions in the country do not have clinical pharmacologists responsible for achieving the effectiveness and safety of pharmacotherapy ,17,18,19For the rational use of antibiotics in Kazakhstan and optimization of procurement, there is a need to decentralize the procurement of antimicrobial drugs. This practice has long been widespread in many countries of the world. Although there is evidence on the negative aspects of the policy of decentralizing the procurement of antibiotics in the available literature, such as problems of logistics and regulation , the indTaking into account the results of the study, where the consumption of the Access group was 29.6% (<60% according to WHO), as well as the irrational use of antibiotics  in the country, it is necessary to introduce the WHO AWaRe classification database in the Republic of Kazakhstan as a tool for setting performance targets and guiding optimal use of antibiotics. It will also allow for regular monitoring of antibiotic use and quality surveillance activities, taking into account the most recent evidence on the rational use of antibiotics.Thus, based on the results of our analysis, we conclude that further research is needed, the results of which will allow the development of a comprehensive policy to contain AMR in Kazakhstan.The disadvantage of this study is that the data was obtained from free medical care, and does not include data from the private health sector in Kazakhstan, which could provide data on antibiotic over-the-counter dispensing. Unfortunately, the data of private medical institutions on the consumption of antimicrobial drugs, as well as the appointments of doctors from private outpatient clinics are not integrated with the country’s compulsory social and medical insurance system and cannot be officially registered.This is a retrospective pharmacoepidemiological study conducted using the ATC/DDD  methodology, where the calculated average maintenance daily dose of drugs was calculated per 1000 inhabitants per day in Kazakhstan. Monitoring the consumption of antibacterial drugs using the ATC/DDD methodology made it possible to standardize indicators of antibiotic consumption at the international level. This, in turn, allowed us to identify the disadvantages and advantages in the consumption of antibiotics in Kazakhstan, to conduct a comparative analysis.The calculation of the consumption of antibiotics corrected to the number of inhabitants was carried out according to the formula:The DDD values were obtained from the website of the WHO Collaborating Center for Drug Statistics Methodology . It shouThis paper analyzed the data of the Ministry of Healthcare of the Republic of Kazakhstan on the purchase of medicines by a Single Purchaser and the number of medicines sold for 2017–2019. The Single Purchaser of Kazakhstan is SK Pharmacy, which deals with the centralized procurement of medicines within the guaranteed volume of free medical care in the compulsory social health insurance system. The study did not include data on over-the-counter antimicrobial use.Data on the population of the country for the study period were taken from the annual statistical compilations “Main socio-economic indicators of the Republic of Kazakhstan” of the Committee on Statistics of the Ministry of National Economy of the Republic of Kazakhstan .The 2019 Access, Watch, and Reserve (AWaRe) classification was used to assess the rational use of antimicrobial agents . AccordiThe Watch group includes antibiotics with higher resistance potential and most of the antimicrobial drugs that have a relatively high risk of bacterial resistance selection. Watch group antibiotics should be a priority as key goals of management and monitoring programs. The Watch group includes 110 antibiotics, 11 of which are included in the WHO EML as first or second variants of empirical treatment options for certain infectious syndromes.The Reserve group includes antibiotics and antibiotic classes that should be used to treat confirmed or suspected infections with multidrug-resistant organisms. A total of 22 antibiotics were assigned to the reserve group. Seven antibiotics of the reserve group are listed in the WHO EML. Traffic light color codes have been proposed to denote different categories: access antibiotics (green), surveillance antibiotics (yellow), and reserve antibiotics (red).The results of our study showed a disturbing picture of the irrational consumption of antibiotics of systemic effect in Kazakhstan. There is a negative trend in all three categories of the WHO AWaRe classification. We found that over the period studied, the consumption of Access antibiotics decreased from 39% to 30%. At the same time, as a result of comparing the top 10 most frequently consumed antibiotics, we saw a slightly different picture with fluctuations and a sharp decline in the consumption of Access antibiotics in 2018 (up to 15.5%).It was revealed that antibiotics of the Watch group are widely consumed in Kazakhstan. In 2019, antibiotics of this group were used in 66.1% of cases of doctor’s prescriptions, which is 4.5% more than in 2017. In 2019, Linezolid entered the top 10 of the most consumed oral antibiotics in the country as a Reserve drug. In general, in Kazakhstan, there is a predominant consumption of parenteral forms of antibiotics of systemic effect. This is probably due not only to the empirical prescription of systemic antibiotics but also to the presence of antibiotic resistance to the drugs of choice. It was also revealed that for the period studied, there was a combined systemic drug in the list of the Single Purchaser, which is included in the WHO list of antibiotics not recommended for use.Data on the consumption of systemic antibiotics in Kazakhstan show that the current national pharmaceutical policy requires improvement and the inclusion of indicators to improve the rational use of antibiotics and reduce the spread of AMR. There is a need for further research to study the problems of irrational use of antibiotics in more detail and to clarify the reasons for non-compliance with the WHO recommended AWaRe classification.


However, the conductive fillers—filled thermoplastic polymers commonly used in the development of functional textiles through 3D printing technology and most specifically through Fused Deposition Modeling (FDM) process—are not appropriate for textile applications as they are excessively brittle and fragile at room temperature. Indeed, a large amount of fillers is incorporated into the polymers to attain the percolation threshold increasing their viscosity and stiffness. For this reason, this study focuses on enhancing the flexibility, stress and strain at rupture and electrical conductivity of 3D-printed conductive polymer onto textiles by developing various immiscible polymer blends. A phase is composed of a conductive polymer composite (CPC) made of a carbon nanotubes (CNT) and highly structured carbon black (KB)- filled low-density polyethylene (LDPE) and another one of propylene-based elastomer (PBE) blends. Two requirements are essential to create flexible and highly conductive monofilaments for 3D-printed polymers onto textile materials applications. First, the co-continuity of both the thermoplastic and the elastomer phases and the location of the conductive fillers in the thermoplastic phase or at the interface of the two immiscible polymers are necessary to preserve the flexibility of the elastomer while decreasing the global amount of charges in the blends. In the present work based on theoretical models, when using a two-step melt process, the KB and CNT particles are found to be both preferentially located at the LDPE/PBE interface. Moreover, in the case of the two-step extrusion, SEM characterization showed that the KB particles were located in the LDPE while the CNT were mainly at the LDPE/PBE interface and TEM analysis demonstrated that KB and CNT nanoparticles were in LDPE and at the interface. For one-step extrusion, it was found that both KB and CNT are in the PBE and LDPE phases. These selective locations play a key role in extending the co-continuity of the LDPE and PBE phases over a much larger composition range. Therefore, the melt flow index and the electrical conductivity of monofilament, the deformation under compression, the strain and stress and the electrical conductivity of the 3D-printed conducting polymer composite onto textiles were significantly improved with KB and CNT-filled LDPE/PBE blends compared to KB and CNT-filled LDPE separately. The two-step extrusion processed  Fused Deposition Modeling (FDM), a 3D printing technique, is used to deposit fused conductive thermoplastic polymers onto textile materials, following, for instance, a desired pattern and a defined number of layers. This technology has drawn the attention of several researchers in the field of functional textiles as it allows the integration of sensors, antennas and conductive tracks on the surface of the textile materials ,9,10,11.The most important properties are the deformations, the tensile properties, the abrasion resistance, the washability and the adhesion between the textile and the printed track. The adhesion between the 3D-printed layers and the textile has already been investigated by a few researchers ,8,10,12.High-density polyethylene (HDPE) is a polyolefin thermoplastic already used in 3D printing by Schirmeister et al. . DespiteThe main target of this research work is to enhance the flexibility, stress and strain at rupture and electrical conductivity of 3D-printed conductive polymer onto textiles by producing immiscible carbon nanotubes (CNT) and highly structured carbon black known as Ketjenblack (KB)-filled low-density polyethylene (LDPE)/propylene-based elastomer (PBE) blends. The rheological and electrical properties of the CPCs/PBE blends, as well as the prediction of the location of the fillers in the various studied blends, were investigated. In addition, deformation under compression, strain and stress and the electrical conductivity of the 3D-printed CPCs/PBE blends onto textiles were explored. In this study, the appellation “3D-PPOT conductive materials” means 3D-printed conductive polymers on textiles materials.3 density . Five measurements of the diameter were necessary to guarantee a standard deviation of 5%. For each monofilament, the diameter was homogenous within the filament length. c = 40 °C and Tc = 70 °C) and brown (Tm = 65 °C and Tc = 100 °C) are the ones of propylene and ethylene, respectively. Besides, one melting peak (Tm = 115 °C) and two crystallization peaks (Tc1 = 110 °C and Tc2 = 65 °C) were detected for LDPE. In the LDPE/PBE polymer blends, a merge of two melting peaks was visualized at 110 °C and another melting peak at 70 °C was recorded. Two crystallization peaks at 105 and 38 °C of the polymer blends are pictured. Thus, these observations demonstrated that, in the polymer blends, LDPE and PBE are two immiscible polymers.60/PBE40 is higher than the one of the PBE. Ku and Lin already explained this phenomenon as an increase of the surface area of incompatible inter-phases of the polymer blends [The melt flow index (MFI) values of the biphasic LDPE/PBE blends are represented in r blends . In our The visualization of the morphologies is very important as it gives information on the final properties of the biphasic blends. LDPE is denser than PBE; consequently, on the SEM images presented in The location of the KB and CNT in the LDPE/PBE blends, the morphology, rheology and electrical properties and DSC analysis of the LDPE/PBE biphasic polymer blends are approached in this section. a)Prediction of the Location through Theoretical ModelsA−B is the wettability coefficient between the polymers A and B, γfiller 1-B is the interfacial energy between filler 1 and polymer B (Nm/m) and γA-B is the interfacial energy between polymer A and polymer B. In order to calculate the wettability coefficient, the contact angles of PBE with water and α-Bromonaphtalene were measured and are listed in earchers ,20,42, t1)The wettability coefficient is lower than −1 and the filler 1 is located in the polymer B;2)The wettability coefficient is between −1 and 1 and the filler 1 is found at the interface of the two polymers;3)The wettability coefficient is higher than 1 and the filler 1 is in the polymer A.Several scenarios can happen:It was found that the wettability coefficient was between -1 and 1 for KB and CNT nanoparticles which are both located at the interface. b)Location of Fillers through SEM ImagesThe location of KB and CNT nanoparticles in the The morphology of the However, as shown in The effect of KB and CNT percentages on the rheology properties through MFI analysis was also investigated . It was The effect of CNT and KB fillers on crystallinity behavior of the conducting blends was also approached and the melting and crystallization curves are presented in The electrical conductivity of the conductive biphasic polymeric blends is an important property to study for them to be applicable in smart textiles through 3D printing techniques. The need for developing biphasic polymers with co-continuous phases is justified by an enhancement of the electrical conductivity while decreasing the percolation threshold with a low amount of fillers in the blends ,43. The The amount and dispersion of the KB and CNT fillers in the LDPE highly influence the electrical conductivity of the final LDPE-based CPC. Indeed, at certain filler contents, the CPC might have reached the percolation threshold and become conductive. However, once the CPC is blended with PBE, the percolation threshold could change due to a different dispersion and distribution of the fillers in a larger volume of the biphasic polymers and also the modification of the morphology of the biphasic blends. A double percolation threshold occurs: a percolation of fillers and another one of CPC phases. Thus, the fillers are diluted in the blends and higher contents of fillers (CNT and KB) are necessary to reach the percolation threshold. In other words, the electrical conductivity depends on the global  percentage of KB and CNT in the blends . By mixiPreviously, it has been demonstrated that the electrical properties of the LDPE-based CPC/PBE blends decreases with an increase of the PBE content because the fillers are diluted. As a result, novel conducting LDPE/PBE blends at similar filler ratios were developed and characterized. The targeted global CNT and KB ratios were 2.5wt% and 10wt% respectively. In other words, depending on the weight percentage of CNT and KB-filled LDPE and PBE added to the CNT and KB-filled LDPE/PBE blends, the quantity of CNT and KB (in wt%) incorporated into the LDPE at the first step was determined in order to obtain final weight percentages of CNT and KB equal to 2.5wt% and 10wt%, respectively. Thus, the filler ratios in the polymer blends were constant for any blends. The details of the amount of CNT and KB added in LDPE are presented in The morphology of the blends M images . It coulThe location of KB and CNT nanoparticles in the BE phase a,b. Wher in LDPE c,d.The values of the melt flow indexes at 245 °C/10 kg and 200 °C/2.16 kg of the nanocomposites blends are shown in r blends . The higmposites . Thus, t. This might be due to the higher amount of fillers which highly block the molecular chains of LDPE and PBE if there is a migration of the fillers in the PBE. By increasing the percentage of PBE, there is an increase of the MFI. Indeed, if there is no migration of fillers to PBE in the The extrusion of the nanocomposite blends in two steps led to a more selective location  of the fPE/40PBE  because PE/40PBE  which blThe electrical conductivity of the conducting polymer composites monofilaments was determined and is presented in The tensile properties of the conducting nanocomposite polymers of the design of experiment number 2 deposited onto textiles through 3D printing were investigated in the cross and machine directions. Cross and machine directions correspond to the orientation of the fabric for the 3D printing. Eutionnat-Diffo et al.  demonstrThe strain of the conducting polymer composites 3D-printed onto fabrics was improved if they were blended to propylene-based elastomer (PBE) . Indeed,The 1-step extruded CPCs/PBE blends presented a lower strain at rupture, which might be due to the migration of the fillers to the elastomer’s phase. Indeed, the creation of the new networks reduced the mobility of the macromolecular chains of the soft segments of the PBE, and thus decreased its elasticity.The permanent and elastic deformations of the 3D-printed conducting biphasic blends of the design of experiment 2 were explored cf. . PreviouThe electrical conductivity of the CNT and KB-filled LDPE/PBE biphasic blend 3D-printed onto textiles was measured and reported in In this study, flexible and conductive monofilaments for functional textiles through 3D printing of biphasic polymer blends onto textiles were developed and characterized. Indeed, immiscible carbon nanotubes (CNT) and Ketjenblack (KB)-filled low-density polyethylene (LDPE)/propylene-based elastomer (PBE) blends at different ratios were created in order to enhance the flexibility, stress and strain at rupture and electrical conductivity of these conductive polymer composites 3D-printed onto textiles. The important requirements to improve these properties were the co-continuity of both the thermoplastic and the elastomer phases and also the location of the conductive fillers in the thermoplastic phase or at the interface of the two immiscible polymers. Indeed, the selective location of the fillers in the thermoplastic phase allowed the creation of a highly structured network between the KB and CNT fillers while maintaining the flexibility and elasticity of the PBE phase conferred by its soft segments. The findings demonstrate that in case of the use of a two-step melt processing, the CNT and KB particles are found to be preferentially located at the LDPE/PBE interface and in the LDPE phase and at the LDPE/PBE interface, respectively. These selective locations support the extensions of the co-continuity of the LDPE and PBE phases over a much larger composition range. Therefore, the viscosity and electrical conductivity of monofilament, the deformation under compression, the strain and stress and the electrical conductivity of the 3D-printed conducting polymer composite onto textiles were significantly improved with KB and CNT-filled LDPE/PBE blends compared to KB and CNT-filled LDPE. The two-step extrusion processing of the


Non-point source (NPS) pollution simulation in control units can identify critical pollution source areas and make Best Management Practices (BMPs) more effective for the responsible parties. In this study, the control unit division method is introduced, and the spatial and temporal distribution characteristics of NPS pollution in the Guishui River Basin of Northern China are analyzed using the Soil Water Assessment Tool (SWAT) model. In addition, five BMP scenarios were designed for environmental and cost-benefit analyses. The results show that the loss of total nitrogen (TN) and total phosphorus (TP) is concentrated in the rainy season, and the loss of TN and TP is mainly distributed in the middle and lower reaches of the main stream of the Guishui River. This area accounts for 22.34% of the basin area. The vegetated filter strips (VFS) scenario had the best environmental benefits with average TN and TP reduction efficiencies of 63.4% and 62.6%, respectively. The Grassed Waterway was the most cost-effective scenario measure, cost-benefit (CE) values of TN and TP were 1798.13 g/€ and 601.56 g/€. Generally, research on NPS pollution using control units can more clearly identify the critical source areas of pollution than other methods, and provides technical support for watershed management decision makers. At present, most river and lake ecosystems worldwide have encountered problems such as water pollution and degradation of ecological functions, that have seriously affected the sustainable development of economic societies . A surveIn the area of basin water environment management, the main purpose of dividing control units is to deconvolve complex basin water environmental problems into each control unit, so that specific water basin water environmental management measures and policies can be effectively implemented to improve the water quality of the river basin . The conThe United States agencies usually study and manage the pollution in control units taking the basin as the control unit and the control unit’s water quality as the goal. The concept of China’s control unit was developed in researching water environmental capacity and total amount control technology during the “Sixth Five-Year Plan” and “Seventh Five-Year Plan”, and the concept of three-level management of the planning area, control area, and control unit was gradually proposed . HoweverThe soil and water assessment tool (SWAT) is a long-period distributed watershed hydrological model, which can predict the production and pollution of different regions in the basin under different soil types, land use types, and management measures. It has gradually become an indispensable tool in water resources and water environmental protection management planning and is commonly used to assess the long-term impact of land management models on water flows, sediment, and agricultural nutrients in complex watersheds . With thIn view of this problem, this study introduces a set of control unit division methods, and according to these methods, the control units of the Guishui River Basin in Northern China are divided. The Guishui River Basin is located in the Yanqing District of Beijing and is located in the Beijing-Tianjin-Hebei eco-economic development zone. In 2022, the Yanqing District will host the World Winter Olympics; thus, higher requirements are imposed on the quality of the water environment. In this study, we used the SWAT model to analyze the distribution characteristics of NPS pollution in the Guishui River Basin based on the control unit, and established five BMP scenarios to evaluate the environmental and cost benefits of each scenario. Based on the conclusions of this study, the critical source area of NPS pollution is located in the control unit, and management decision makers can adopt BMPs for the critical source area to provide technical support for management decision makers in identifying and regulating NPS pollution in the basin.2. The geographical location of the Guishui River Basin is shown in The Guishui River Basin is located in Yanqing District, Beijing, 74 km from Beijing City. It is the northern gateway of Beijing, and the watershed is located between 115°48′51″ and 116°20′42″ E, and 40°21′50″ and 40°38′40″ N. The total length of the Guishui River is 74.3 km, and its drainage area is 724.6 kmThe land use in the basin b is domiThe data collected in the control unit include: administrative divisions, underlying areas of river basins, river systems, locations of control sections, and sources of pollution:(1) Administrative Division InformationAccording to the needs of regional watershed water environment management, the basic unit of administrative division is selected; for example, village-level zoning data are selected for village-level management, and township-level zoning data are selected for township management.(2) Underlying Surface InformationThe underlying data of the basin include digital elevation maps (DEM), types of land use in the basin, and characteristics of specific surface units. (3) Source of PollutionPollution source information mainly includes the main pollution sources and their distribution in the river basin, as well as the main sewage outlets and their distribution in the river.(1) River Basin IntegrityThe principle of river basin integrity means that according to the characteristics of the hydrological cycle of the river basin, the division of control units must ensure the integrity of the river basin and uniformly plan the division scheme of the river basin control unit.(2) Principle of Determining Land by WaterThe control unit is the surface area corresponding to the land and water, and the natural water system is the benchmark for land area division. The land confluence range is determined according to the characteristics of the natural watershed to form a land–water combined unit.(3) Principle of Completeness of Administrative DivisionThe boundary of the control unit does not cross the boundary of the administrative district. For the only district or county leading the sewage discharge, the entire district or county is assigned to a certain control unit. For districts and counties that do not have the only dominant drainage destination, districts and counties can be split into different control units.The control unit division steps  are as f(1) Related Data CollectionCollect the data required for the division of control units proposed in (2) Watershed Boundary Identification and Sub-Watershed DivisionBased on digital elevation map (DEM) data, hydrological analysis tools in GIS are used to form watershed boundaries. The river basin data are extracted and compared with actual river network water systems. Sub-watersheds are divided by superimposing control sections, land use, and other data. They are spatially continuous, and there is no intersection in the upstream and downstream relationships of the water system. There are obvious differences in the attributes of vegetation and land use among different zones, and different zones show different ecological and hydrological characteristics.(3) Analysis of Pollution Characteristics in River BasinsSimple analysis of types  and distribution of pollution sources in the basin, based on the characteristics of the water system and the sub-basin, the topological relationship among point sources and non-point sources in the river basin and their corresponding sewage discharge outlets and tributaries into the river basin is roughly established. It is important that point sources and non-point sources in the same control unit flow into the same tributary tributary or the same main stream section.(4) Superimposed Administrative DivisionBased on the results of small scale partitioning, the control unit is generated by superimposing the results with the data of administrative division and administrative station.(5) Partition Result VerificationAccording to the above four steps, the control unit should be connected with the place where the river basin is located and verified by experts. If it meets the needs of the water environment and water ecology management in the river basin, it should be regarded as the final result of the division of the control unit, otherwise, further adjustments should be made. The adjustment is mainly based on the situation of sewage going to and collecting water on the spot, and systematic investigation is made of the hydrology, water environment, administrative division, and social and economic status of the river basin, to make the result of the final division of control unit more reasonable.NSE) and coefficient of determination (R2) were used to evaluate the simulation effect of the model [NSE is the Nash-Sutcliffe efficiency coefficient, iO is the observation at time i, iP is the analog value at time i, R2 is the certainty coefficient, and NSE > 0.75, the simulation effect is considered very good, when 0.50 ≤ NSE ≤ 0.75, the simulation effect is satisfactory, and when NSE < 0.50, the simulation effect is not good. When R2 ≥ 0.85, the simulation effect is very good, when 0.85 > R2 ≥ 0.60, it indicates that the simulation effect is satisfactory, and when R2 < 0.60, it indicates that the simulation effect is not good.The key data collection of the SWAT model in this study is shown in he model ,23,24, ap-value determines the significance of sensitivity, the closer it is to 0, the more significant it is. The sensitivity results and parameter values are shown in Analysis of 26 parameters affecting runoff and nitrogen and phosphorus based on the SUFI-2 algorithm in SWAT-CUP. In the parameter sensitivity analysis results, the t-star value gives the degree of sensitivity, the larger the absolute value, the more sensitive it is. The NSE) ≥ 0.5 and R2 ≥ 0.6, indicating that the model has good applicability.According to the results, CANMX is the most sensitive parameter in the surface runoff simulation, followed by CN2 and GWQMN. CDN is the most sensitive parameter in the TN simulation, followed by SOL_NO3 and SDNCO. SOL_ORGP is the most sensitive parameter in the TP simulation, followed by P_UPDIS and PHOSKD. According to the current research on BMPs, they can be divided into structural measures and nonstructural measures . Among tThe Grassed Waterway scenario is a grass-planting channel for conveying field runoff. It has been proven to be an effective treatment measure. Mainly through the plants in the river channel, the flow velocity of field runoff is reduced , so thatVFS removes contaminants in a similar way to Grassed Waterways. VFS is a densely vegetated strip used to intercept runoff from upslope sources, effectively reducing pollutants. The VFS width was set at 5 m to assess the reduction and cost of nitrogen and phosphorus loads. The VFS width was manipulated by modifying the parameter FILTERW in SWAT . Based on current basin crop management practices, in nonstructural measures, we set fertilization reduction (10% and 20% of the current use amount) and no-tillage to explore the impact of nonstructural measures on nitrogen and phosphorus reduction efficiency.CE). CE represents the reduction in pollution load per euro; the higher the CE value, the better the cost-effectiveness of the measure scenario. Conversely, the lower the CE value, the lower the cost-effectiveness of the scenario, that is, the lower the amount of pollutant reduction at the same cost, the less likely it is to be adopted by policy makers [CE stands for cost-effectiveness (kg/€); BASLOAD and BMPLOAD represent the NPS production (kg) under the benchmark status quo and the measured scenario, respectively; and Cost represents the cost (€) of the scenario measure deployment.On the premise of meeting the requirements of environmental quality, economic cost becomes an important factor influencing BMP screening. Cost-benefit analysis is an effective BMP optimization method to evaluate various measures according to their costs and benefits. In this study, the difference between the baseline NPS pollution load and the NPS pollution load under various scenarios was taken as the environmental benefit, and the ratio between the environmental benefit and the calculated measure scenario cost was taken as the cost-benefit value  Simulation of S1According to the analysis of the results, the reduction efficiency of TN and TP in Grassed Waterway were 13.2 to 46.3% and 15.6 to 49.6%, and the average reduction efficiency was 35.1% and 33.7%, indicating significant reduction effect. (2) Simulation of S2The reduction efficiencies of TN and TP in VFS were 33.6–76.6% and 43.6–74.2%, and the average reduction efficiencies were 63.4% and 62.6%. S2 is the measure with the highest reduction efficiency out of all five scenarios. (3) Simulation of S3 & S4In S3 and S4, when the fertilizer application amount was reduced by 10%, the reduction efficiencies of TN and TP were 0.3–4.1% and 0.7–12.9%, and the average reduction efficiencies were 2.4% and 4.4%. When the application amount was reduced by 20%, the pollutant reduction efficiency was improved. The reduction efficiencies of TN and TP were 0.5–8.2% and 1–19.4%, and the average reduction efficiencies were 4.7% and 8%. Overall, fertilizer reduction measures had a certain effect on reducing pollutants, but the effect were not particularly significant. This view is consistent with related research . (4) Simulation of S5The results show that the reduction efficiencies of TN and TP were 0–0.9% and 40.2–6.5%, and the average reduction efficiencies were 0.2% and 0.8%. Compared with other scenarios, S5 had the lowest pollutant reduction efficiency.(1) Cost Accounting2O2) is ~0.7 €/kg. The measure layout area is the farmland area. According to the literature, the cost of no-tillage measures is ~13.5 €/ha [3.5 €/ha .(2) Cost-benefit analysisCE value of pollutants in each scenario. It can be clearly seen from the figure that the CE value of the structural measures (S1 & S2) established in this study is much higher than for the nonstructural measures (S3 & S4 & S5). Among the structural measures, the highest CE value is the grass-planting river. The benefits of TN and TP are 1798.13 g/€ and 601.56 g/€. Among nonstructural measures, the CE value of no-tillage is the lowest, and the benefits of TN and TP are 0.57 g/€ and 0.8 g/€. It can be seen that the implementation of no-tillage measures in the Guishui River Basin has no obvious effect on pollutant reduction. Although the use of fertilizer reduction measures can reduce pollutants to a certain extent and save fertilizer purchase costs, the resulting reduction in crop production will reduce enthusiasm for the measure. Therefore, managers and decision makers should find the balance between fertilizer reduction and crop yield. From the long-term perspective of CE value analysis and watershed management, structural measures are the most effective measures to control pollution load, although this does not mean that only structural measures are used in watershed management. As structural measures occupy a certain amount of land resources, there will be contradictions between governance measures and land resources in future management. Therefore, in the actual governance process, the layout of BMPs needs to take into consideration the land resources, comprehensively consider the local socio-economic level, and ecological environment status, and adopt appropriate BMPs according to the local conditions.The novelty of the study is included in the Introduction in terms of mentioning the limitations of the existing approach. However, the SWAT model pollution load output results are based on the sub-basin or hydrologic response unit (HRU) as a unit, and only subsequently the critical source areas of the pollution source in the basin are identified. BMPs are usually established based on critical source areas, which only consider the “quantity” of the pollution load; that is, they are only located in heavily polluted areas. If the areas include more than two administrative areas, they will not be conducive to implementing the measures to the responsible body.This study systematically applies a well-known methodology to non-point source pollution study for the Guishui River Basin, and tests various methodologies for reducing it. Because of the systematic design of the study, the outcomes are well suited for policy implementation. Based on the control unit scale, the SWAT model was used to analyze the cost-effectiveness of BMP implementation in the Guishui River Basin, and the scenarios and measures were simulated and analyzed from environmental benefits and economic costs perspective:(1) This study introduces the division method of the river basin control unit. The division of the control unit can effectively implement the measures to the responsible subjects. The control unit analyzes the pollution load of the river basin and clarifies the responsible party.(2) The SWAT model verified by parameter calibration shows good applicability to the simulation of NPS pollution in the Guishui River Basin. Based on the control unit scale, the spatial and temporal distribution of NPS pollution in the river basin is analyzed. The results show that the time distribution of pollutants in the river basin is extremely uneven, and the pollutant output is mainly distributed in the rainy season. Rainfall runoff is the main influencing factor NPS pollution output. Similarly, there are differences in the spatial distribution of pollutant output. In 2016, the TN loss intensity of the Lushui River Basin was between 0.24 and 0.36 kg/ha, and the TP loss intensity was between 0.078 and 0.146 kg/ha. The lower reach of the Guishui River Basin  is a critical source area for pollutant loss. Therefore, the implementation of governance measures should take into account the spatiotemporal distribution of pollutants, which can be adjusted in time to control units.CE value of structural measures set in this study is much higher than nonstructural measures. S3 is the most cost-effective measure, the values for TN and TP are 1798.13 g/€ and 601.56 g/€, Compared with S4, S3 shows a better pollutant reduction rate when using fewer land resources.(3) This study established five scenarios, including structural and nonstructural measures. The SWAT model was used to simulate the pollutant reduction in each scenario. Simulation results show that the reduction efficiency of structural measures is much higher than that of nonstructural measures, of which S2 pollutants have the highest reduction effect. The average reduction rates of TN and TP were 63.4% and 62.6%, respectively. The S5 pollutant reduction effect was the lowest, and the average reduction rates of TN and TP were only 0.2% and 0.8%. Similarly, under the condition of economic cost, the In the selection of BMPs in the river basin, in consideration of environmental and economic benefits, factors such as land resources, government development planning and technological level must also be considered, as decision makers are required to take all factors into consideration. Therefore, selecting a variety of effective BMPs reasonably, and providing long-term and effective plans for local environmental protection and sustainable development is key.In addition, the SWAT model was based on the parameters for the study area only and did not verify those for different areas of the same watershed. This is likely to cause errors in the calculation of runoff and pollution in each sub-watershed. Further research should be conducted on the parameters of each sub-basin in the future.


In this work, we present a series of hammering tests on full-scale unit-plate ballastless tracks used for long-span bridges. There is no denying that it is a new attempt to pave ballastless tracks on high-speed railway long-span bridges; the related issues deserve to be studied, and especially the vibration characteristics. Hence, the vibration characteristics and transmission rules of the ballastless track with geotextile or rubber isolation layers are explored, and the vibration reduction effect of the rubber isolation layer is analyzed. The main conclusions are as follows: the isolation layers change vibration modes and transmission characteristics of ballastless tracks; the introduction of the rubber isolation layer makes the excited vibration frequency range of the ballastless track concentrated; and the vibrations of the ballastless track with the rubber isolation layers are stable. Moreover, the rubber isolation layer has an obvious attenuation effect on vibration transmission in ballastless track structures. When the vibration is transmitted from the rail to the bridge deck, the vibration level differences of the ballastless track with rubber isolation layers are 20 dB larger than that of the ballastless track with the geotextile isolation layers. The vibration attenuation rate of the rubber isolation layer is about ten times larger than that of geotextile isolation layer. Nowadays, high-speed railways have developed rapidly around the world, especially in China . High-spBased on this, many authors have carried out some experimental measurements and numerical simulations of train-induced vibrations in recent years ,4,5,6,7.However, systematic studies on the vibration characteristics of the unit-plate ballastless track systems are still quite limited among railway researchers. The types of unit-plate ballastless tracks are usually paved on high-speed railway long-span bridges, and some new components (such as new type isolation layer) are employed in ballastless tracks to improve their mechanical behaviors . As is wAt present, model testing is always used to investigate the dynamic characteristics of railway tracks ,18 and uIn China, the unit-plate ballastless track mainly includes CRTS I type double-block ballastless track, CRTS III type ballastless track, etc. ,21,22. TThe CRTS I type double-block ballastless track was first introduced and developed by Rheda (2000) and was re-innovated based on China’s actual situation. Additionally, it has already been used in Wu-Guang and He-Fu passenger dedicated lines in China. The length and width of this type of unit-plate ballastless tracks are 5920 and 2800 mm. The thickness of the concrete track slab and basement are 260 and 240 mm. Both the basement and track slab are made of C40 concrete, and CHN60 rail (similar to UIC60 rail) and WJ7-B constant resistance fasteners are employed in these ballastless track systems .3. More detailed information about the isolation layers can be found in Ref [More important, the geotextile isolation layer has been widely used in the construction of CRTS I type double-block ballastless track. The thickness of the geotextile layer is always 4 mm, and it meets all the requirements in China standard . The rubd in Ref . The uniIn this work, the modal characteristics, dynamic behaviors, and vibration transmission of the unit-plate ballastless tracks were investigated by conducting a series of hammering tests. The hammering test, which is to apply a pulse excitation to the structure, is a test on the structure in the frequency range to be studied . More deIn the modal test, four positions on the concrete track slab were randomly selected for excitation. Additionally, in the vibration transmission characteristic test, the excitation points were on the top surface of rails, and five repeated hammering tests were carried out in each working condition, labeled as Test #1 to Test #5.In modal measurement procedure, a series of measuring points were evenly arranged on the top surface of concrete track slab, and an acceleration sensor was installed on each measuring point to obtain vertical acceleration. The layout of these measuring points is shown in In this work, the vertical responses of the unit-plate ballastless tracks with different isolation layers were measured to research the vibration characteristics. Two test conditions were organized and carried out, labeled as Condition #1 and Condition #2, respectively. Condition #1: impacting rail at central position of the ballastless track with geotextile isolation layers; Condition #2: impacting rail at central position of the ballastless track with rubber isolation layers. The vibration characteristics of different ballastless tracks were studied by symmetrical arrangement of measuring sensors in these two working conditions. The arrangements of measuring sensors are shown in The modal characteristics of the track slab in these two types of ballastless tracks were obtained according to the test data of hammering tests. The first three orders of modal modes of the track slab are shown in It can be seen from The time-history vibration curves of the rails can be obtained by the acceleration sensors installed in this work, and then the frequency-history vibration curves can be obtained by the Fast Fourier Transform technique. Based on this, the time-domain and frequency-domain results of some measuring sensors on rails in these two conditions are shown in It can be seen from The time-domain and frequency-domain results of some measuring sensors on concrete track slabs in these two conditions are shown in As shown in Based on the vibration characteristics of the ballastless tracks, the vibration transmission laws of the track slab in these ballastless tracks are studied. In this work, the virtual vibration values of each measuring sensor on ballastless track structures are compared and analyzed to study the vibration transmission and reduction characteristics. The virtual vibration value mula (1) :(1)armsIn Formula (1): Since the vibration attenuation is not apparent in the longitudinal and transverse direction of the ballastless track, the attenuation rate is expressed in the form of percentage; while in the vertical direction of the ballastless track, the acceleration of each layer in the ballastless track has a large attenuation, so it is more reasonable to describe the vertical attenuation rate by using the vibration acceleration level differences.At present, the vibration acceleration level is indicated by the following Formula (2) :In Formula (2), Then the acceleration level difference between A and B can be expressed as the following Formula (3):Therefore, the attenuation rates and the level differences of the vibrations between different measuring points are taken as the evaluation indexes to investigate the vibration characteristics and transmission law of the two types of ballastless tracks in the longitudinal, transverse and vertical directions in these two conditions. Additionally, the vibration acceleration index of other measuring points is compared with that of the base point, which is next to the exciting location.The acceleration values of the measuring sensors on rails in Condition #1 and Condition #2 are compared and analyzed. Based on the virtual values of sensors R1F1 and R1J1 in these two conditions, the attenuation rates of other measuring points relative to the test results of sensors R1F1 and R1J1 are calculated, respectively. The longitudinal vibration transfer characteristics of rails are shown in As shown in The test data of these sensors on rails in the two conditions are selected to study the longitudinal transmission rules of rail vibration in frequency domain, as shown in For the ballastless tracks with different types of isolation layers in this work, the variations of acceleration level differences of the rail in frequency range of 0 to 1000 Hz are similar. Due to the existence of the rubber isolation layer, the acceleration level difference in Condition #2 is about 20 dB larger than that in Condition #1, which means that rubber isolation layer has a better damping effect. Moreover, there are significant differences in the acceleration level differences between the two types of ballastless tracks in frequency range of 2000 to 3000 Hz, which shows that this frequency range is sensitive to the vibration reduction and isolation effect of the rubber isolation layer.The test data of the sensors on the track slabs in Condition #1 and Condition #2 are selected for further research. Based on the virtual values of sensors S1F1 and S1J1 in the two conditions, the attenuation rates of other measuring points are calculated. The vibration transfer rules of the track slab are shown in It can be seen from Moreover, the test data of the sensors on track slab in Condition #1 and Condition #2 are selected, and then the vibration level differences of other measuring sensors are calculated based on the vibration acceleration level of sensors S1F1 and S1J1, so as to study the vibration transmission laws of the concrete track slabs, as shown in As can be seen from The vibration data of different structural layers in these two ballastless tracks in Condition #1 and Condition #2 are selected to study the vertical vibration transmission law. Based on the virtual values of vibration acceleration of sensors R1F1 and R1J1, the vibration level differences of other sensors are calculated, and then the vibration reduction and isolation effect of different types of isolation layers in ballastless tracks are obtained, as shown in It can be seen from Furthermore, the vibration level differences of sensors S1F1 and S1J1 on track slabs are calculated based on the vibration level of sensors R1F1 and R1J1, and the vibration level differences of sensor Q1 on bridge deck are calculated based on the vibration levels of sensors S1F1 and S1J1, so as to study the vertical vibration transmission laws in ballastless tracks with geotextile isolation layers or rubber isolation layers in frequency domain, as shown in As shown in In this work, we conduct a series of experimental research on the modal and vibration characteristics of unit-plate ballastless tracks used for high-speed railway long-span bridges. The main conclusions are as follows.(1)The isolation layers change the vibration characteristics of track slab. The introduction of the rubber isolation layer in the ballastless track greatly reduces the vibration of track slab, and it also changes the vibration characteristics of track slab.(2)The isolation layers effect the vibration transmission characteristics in ballastless tracks. For the ballastless track with geotextile isolation layers or rubber isolation layers, the main difference of rail vibration is in frequency range of 2000 to 3000 Hz, and the reduction effects on rail vibration transmission caused by the rubber isolation layers are apparent. Moreover, the vibrations of the track slabs in ballastless tracks with geotextile or rubber isolation layers are reduced by 30% or 60%, which means that the vibration reduction effect of the rubber isolation layer is significant.(3)The application of rubber isolation layer makes the excited vibration frequency ranges of the ballastless tracks concentrated. Furthermore, the vibration attenuations of the ballastless tracks with rubber isolation layers are stable.(4)In the vertical vibration transmission process of the ballastless tracks with different types of isolation layers, the attenuation laws are slightly different in frequency domain. The vibration attenuation rate of the ballastless track with rubber isolation layers is about ten times larger than that of ballastless track with geotextile isolation layers, and the vibration reduction on vertical transmission in ballastless track with rubber isolation layers is apparent.