China is a large country in terms of coal production and consumption. The fly ash and slag produced by thermal power plants pose a great threat to the environment. To reduce the adverse effects of fly ash and slag on the environment, a mixture of slag and macadam stabilized with cement and fly ash was prepared as pavement base material. Compaction tests, unconfined compressive strength tests, splitting strength tests, frost resistance tests, and ultrasonic tests were performed on the mixture. The results show that with an increase in slag replacement rate, the unconfined compressive strength and splitting strength decreased. However, the adverse influence of the slag replacement rate on unconfined compressive strength and splitting strength of specimens gradually weakened with increasing curing time. The frost resistance of the mixture first increased and then decreased with an increase in the slag replacement rate. When cement content was 5% and the slag replacement rate was 50%, the frost resistance of the mixture was the best. Regression analysis of the ultrasonic test showed that the ultrasonic test can effectively characterize the strength of the mixture and the internal damage degree under freeze–thaw cycles. In conclusion, the slag replacement rate of the mixture is recommended to be ~50%, which has preferable mechanical and frost resistance performance. Coal is the primary energy source for thermal power generation in China. According to available data, ~5.2 trillion kW·h of thermal power was generated in 2019. Approximately 140 million tons of fly ash and slag are generated per trillion kW·h of power generation. Therefore, the amount of fly ash and slag produced by thermal power generation was ~730 million tons in 2019. Compared with the developed countries in the west, the high value-added utilization rate of coal fly ash and slag in China has always been lower. Generally, fly ash is used only as roadbed backfill or in admixtures of concrete and blocks. In Ningxia, Inner Mongolia, Guizhou, and Yunnan, most of the fly ash and slag produced is discharged directly as waste, which not only causes surface and groundwater pollution but also occupies considerable amounts of valuable land resources. This pollution has a severe effect on the quality of life for the surrounding residents and limits the local economic development. Thus, the potential value of fly ash and slag has been extensively explored in previous studies to realize the resource utilization of industrial solid waste ,7,8. UsiXiao et al.  studied Compared with the characteristics of fly ash, slag has larger particles and a porous structure and generally cokes into agglomerates. This material is used in production after being crushed, sieved, and cleaned. Although slag calcined at high temperatures contains lower amounts of harmful substances, the large amount of stacked slag requires abundant land resources and affects plant growth . To reduTherefore, the numerous studies on fly ash or slag as a single admixture have achieved good results. In contrast, relatively little research has been conducted in which the 0–4.75 mm macadam is replaced by slag and is mixed with fly ash as a pavement base material. To explore the influence of fly ash and slag on the road performance of the pavement base mixture, the fly ash and slag produced by the Ningxia Xixia thermal power plant were taken as the research objects to investigate slag and macadam stabilized with cement and fly ash mixtures. Ultrasonic testing was employed to evaluate the mechanical performance, including the unconfined compressive strength, splitting strength, and strength reduction law under freeze–thaw cycles. The objectives of this study are to improve the mechanical properties and frost resistance of traditional cement-stabilized macadam base by adding fly ash and slag, reduce the consumption of macadam, and achieve the purpose of sustainable development by turning waste into treasure. The flow chart of our study is shown in Cement: P·O 42.5 R Ordinary Portland Cement obtained from Ningxia Horse Racing Cement Co., Ltd., Yinchuan, China;Fly ash: grade III fly ash produced by Thermal Power Plant in Xixia District, Yinchuan, China;Slag: slag produced by Thermal Power Plant in Xixia District, Yinchuan, China;Macadam: macadam from Helan Mountain, Yinchuan, China;Water: tap water.The materials used for slag and macadam stabilized with cement and fly ash mixture are as follows:The main mineral and chemical compositions of the slag and fly ash were detected by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The XRD test results of the slag and fly ash are shown in 2, Al2O3, and Fe2O3 with small amounts of alkaline oxides such as CaO and K2O. The mass fraction of SiO2 and Al2O3 in the fly ash is relatively large, accounting for ~78% of the total mass, and the loss-on-ignition is less than 10%, which meets the standard for pavement base filling materials. The mass fraction of SiO2 and Al2O3 in the slag is ~70%, and the alkaline oxide accounts for ~14% of the total. Therefore, the slag has high activity and is weakly alkaline. The slag is composed mainly of glass matrix and nCaO·SiO2. Under the action of water, these alkaline oxides react with SiO2, Al2O3, and Fe2O3 to show hydraulic gelling properties [operties ,20,21,22The natural particle-size distribution of slag is uneven and varies greatly, as shown in For the preparation and curing of specimens, a compaction test was conducted to obtain the optimum water content and maximum dry density of the mixture. Then, cylindrical specimens with a diameter to height ratio of 1:1 were prepared by the static pressing method. The diameter of the specimens was 150 mm, and the compaction coefficient was 0.98. The prepared specimens were wrapped in plastic bags and cured to the corresponding age under standard curing conditions, which were used to test the mechanical properties and frost resistance. The prepared specimens and curing environment are shown in The unconfined compressive strength and splitting strength of the specimens were tested according to the Test Methods of Materials Stabilized with Inorganic Binders for Highway Engineering (JTG E51-2009) . The tesTo evaluate the frost resistance, the specimens cured for 28 days were tested by freeze–thaw cycles. When cured for 27 days, the specimens were soaked in water for 1 day. Then, the immersed specimens were placed in a constant temperature testing machine at −18 °C for 16 h to ensure that a gap of ~50 mm was present around each specimen to facilitate the circulation of cold air. Then, the specimens were placed in a constant temperature flume at 20 °C for 8 h. After the ice melted, they were removed from the sink and allowed to rest for 15 min. Next, the specimens were weighed, and the average value was obtained. The unconfined compressive strength was measured for 5, 10, 15, 20, 25, and 30 freeze–thaw cycles. The frost resistance of the mixtures was comprehensively evaluated based on appearance change, mass loss, and strength loss.Ultrasonic testing was conducted using a nonmetallic ultrasonic analyzer  with a sound time accuracy of ±0.05 μs. After setting the sound time to 0, Vaseline petroleum jelly was applied to the transmitting and receiving transducers as a coupling agent. Then, the transducer was affixed to both sides of the specimen, the sampling was engaged, and the ultrasonic test results were stored. Four points were measured on each specimen. The measuring points are indicated in The compaction tests were conducted on samples 5-SR-0 to 5-SR-100, and the maximum dry density and optimum water content of the mixtures were obtained, as shown in The unconfined compressive strength test results of mixtures 5-SR-0 to 5-SR-100 at different ages are shown in 2 and Al2O3 in the fly ash and slag gradually undergo secondary hydration under the excitation of the cement hydration product Ca(OH)2, resulting in a large number of gel substances such as C-S-H, C-A-H, and ettringite [tringite , as show2 and other active substances that participate in the reaction decreased with further increases in the degree of the secondary hydration reaction, thereby decreasing the rate of secondary hydration [2, Al2O3, and alkaline oxides in the slag, which enabled the reaction of slow secondary hydration in the long curing period. With an increase in the slag replacement rate, the number of active substances in the specimens increased. Thus, more water was needed to achieve the optimum water content to provide the necessary active material and water for the secondary hydration reaction. Therefore, in the latter stage of the curing period, the adverse effect of slag on the strength of the specimens gradually decreased. On the 90th day, the compressive strength of 5-SR-0 was 4.7%, 3.5%, 6.5%, and 8.4% higher than that of 5-SR-25, 5-SR-50, 5-SR-75, and 5-SR-100, respectively. Therefore, the strength growth rate of the specimens decreased significantly during the longer curing period, and the growth was more obvious with an increase in the slag replacement rate. Moreover, unconfined compressive strength of the mixture on the 7th day meets the standard Technical Guidelines for Construction of Highway Roadbases (JTG/TF20-2015) [These gel materials tighten the interfaces among the slag, macadam, and cement mortar, which significantly improves the internal compactness and cementation strength of the specimens. This behavior is shown directly from the improved specimen strength. On the 56th day and 90th day, the strength growth rate of the specimens decreased significantly, at an average of 16.1%; with an increase in the slag replacement rate, the increase in specimen strength was more obvious. This occurred because the amount of Ca(OH)ydration . When th20-2015) . To achiMATLAB was used to fit the unconfined compressive strength formula of the different slag replacement rates at the 7th, 28th, 56th, and 90th day, as shown in x in y is 50.To study the strength development laws of the specimens with different cement contents, it is necessary to determine the optimal slag replacement rate. In this study, three principles were followed when selecting the optimal slag replacement rate. Firstly, the 7-day unconfined compressive strength loss rate of the specimens mixed with slag was controlled within 10%. Secondly, the 90-day unconfined compressive strength loss rate of the specimen was less than 5%. Finally, the slag replacement rate was increased as much as possible. As shown in According to the obtained optimal slag replacement rate of 50%, the unconfined compressive strength values of 2-SR-50 to 5-SR-50 after 7, 28, 56, and 90 days shown in 2 increases, which rushes the hydration rate of the specimens in the early stage [2 in the specimens further increases with a continuous increase in the cement content. However, the content of active substances such as SiO2 and Al2O3, which can participate in the secondary hydration reaction, decreased at the initial stage of curing, and the reaction rate did not show an obvious increase, which directly revealed that the strength growth of the specimens slowed. On the 28th day, the unconfined compressive strength of the specimens was significantly higher than that on the 7th day, and the compressive strength growth rate with the different cement contents was more than 65%. This depended mainly on the secondary hydration reaction and microaggregate effect. On the 56th and 90th day, the strength growth rate of the specimens showed obvious decreases, and the average value was only 15.8%. With an increase in the cement content, the increase in specimen strength was more obvious. This occurred because further increases in the secondary hydration reaction caused gradual decreases in the amount of active substances such as Ca(OH)2, which are mainly involved in the reaction. This resulted in a slower reaction rate. In addition, the increase in cement content caused the content of Ca(OH)2 in the specimens to increase, and a relatively large amount of Ca(OH)2 still reacted with fly ash and slag in the later stage of curing. Therefore, with an increase in the cement content, the specimens can still present a relatively high strength growth rate in the later stages of curing.With an increase in the cement content, the strength increases of the specimens varied among ages. On the 7th day, when the cement content was 2%, 3%, and 4%, the 7-day unconfined compressive strength of the specimens showed obvious increases. When the cement content increased to 1%, the unconfined compressive strength of the specimens increased to 1.3 MPa and 1.1 MPa, respectively. This occurred because with an increase in cement content, the proportion of cement clinker minerals in the specimens increases and the content of Ca(OH)ly stage . When thMATLAB was used to fit the unconfined compressive strength formula of the different cement contents at various ages, as shown in As can be seen from 2 to form dense C–S–H gel and ettringite. The formation of C–S–H gel strengthened the bond of the fly ash and slag particles with the macadam particles and improved the strength and compactness of the specimens [According to the unconfined compressive strength test results, the strength formation mechanism of the specimens was analyzed. The results can be summarized into three main points. First, when the slag is mixed with cement, fly ash, and macadam, the phase composition in the slag pores can be divided into three types. The first is the solid phase, including cement, fly ash, fine slag, and macadam; the second is the liquid phase, including the water molecules; and the third is the gas phase, including the unfilled area in the slag pores. With an increase in curing time, the secondary hydration reaction gradually began in the cement and fly ash in the slag pores to form the C–S–H gel material. These dense gel materials filled the slag pores that improved the high porosity and low density of the slag, which in turn improved its bearing capacity. Second, the cement, fly ash, and fine macadam filled the spaces between the slag particles and the macadam, which created a microfilling effect and improved the compactness and stability of the cement–mortar interface. Third, the fly ash and slag are high-activity substances and contain a certain amount of alkaline oxides. With an increase in the curing time, they fully reacted with the cement hydration product Ca(OH)pecimens . AlthougAccording to the relevant standards for the 7-day unconfined compressive strength of materials stabilized with cement and fly ash, the strength representative value of 95% guarantees a pavement base rate of not less than 4.5 MPa. The strength representative value, As shown in the table, when the cement content was 5% and the slag replacement rate was 100% or less, the representative value of 95% guaranteed a rate strength of 4.5 MPa in the specimens, which meets the technical requirements of extremely heavy and extra-heavy traffic on expressways and first-class highways in China.The results of splitting test results at various ages are shown in The splitting strength of the specimens increased with increases in the cement content and curing age, where the increasing law is similar to the unconfined compressive strength. The splitting strength of 5-SR-0 was higher than that of the specimens mixed with slag, which indicates that the addition of slag had an adverse effect on the splitting strength of the specimens.2 in the specimens, inhibits the growth of Ca(OH)2 grains, and reduces the thickness of the interfacial transition zone. With continued consumption of Ca(OH)2, the amount of the gel material increased, which further increased the splitting strength of the specimens [On the 7th day, the splitting strength of the specimens increased with an increase in the cement content and a decrease in the slag replacement rate. The primary causes and change laws are the same as those in the unconfined compressive strength test. On the 28th day, the splitting strength of the specimens was significantly higher than that on the 7th day, and the average growth rate of the splitting strength was 70.4%. The particle-size distribution of the fly ash was very uniform, and the average particle size was much smaller than that of macadam and slag. These characteristics enable fly ash to be uniformly filled with aggregates to form a tight accumulation system, which makes the secondary hydration reaction more sufficient. However, with an extended curing age, the active substances in fly ash and slag gradually undergo secondary hydration, which consumes the Ca(OH)On the 56th and 90th day, the splitting strength of the specimens with a slag replacement rate of 50% was slightly better than that with rates of 25%, 75%, and 100%. The strength growth law of 5-SR-25 to 5-SR-100 showed that an increase in slag replacement rate caused the splitting strength of the specimens to first increase and then decrease, which was determined by the failure mode of the splitting test specimens. The change rule and strength formation mechanism of splitting strength were similar to those of compressive strength, but the failure modes were different. The specimens were regarded as a composite material composed of slag, macadam, cement fly ash mortar, and transition zone. The compressive failure was caused by the expansion of cracks in the transition zone to cement fly ash mortar and the final formation of multiple main cracks. The splitting failure was caused by expansion of microcracks in the transition zone on both sides; deflection occurred when the interface transition zone was encountered, which ultimately caused the main crack to form. When the slag replacement rate increased from 25% to 50%, the interface transition zone of the micropore structure increased, the continuous deflection of microcracks consumed more fracture energy, and the splitting tensile strength improved . HoweverIn summary, the splitting strength of the slag and macadam stabilized with cement fly ash is the comprehensive embodiment of macadam strength, the hydration reaction degree of cementitious material, and the internal cohesion of the mixture. The strength of the slag aggregate was lower than that of the macadam, which is the main explanation for the generally lower splitting strength of the slag aggregate than that of 5-SR-0. In addition, the porous and noncompact characteristics of slag promote the infiltration of cement fly ash paste into the aggregate, which enhances the compactness and stability of the specimens. In the later stages of curing, the active substances in slag and fly ash undergo secondary hydration, generating large amounts of C–A–H, C–S–H, and other cementitious substances, which improve the internal structure of the aggregate interface zone and increase the strength of the specimens. When the cement content was more than 3% and the slag replacement rate was 50%, the 90-day-splitting strength of the specimens was more than 0.4 MPa, which meets the technical index of highway pavement base material in China .ft is the splitting strength of concrete (MPa), fc is the compressive strength of a concrete cylinder (MPa), and k and n are obtained by nonlinear regression analysis.The above test results show that the unconfined compressive strength of the specimens is positively correlated to the splitting strength, and the relationship between them has become a hot topic for researchers. However, the relationship between unconfined compressive strength and the splitting strength of pavement base materials has been rarely reported. Therefore, based on the commonly used conversion formula relating compressive strength and splitting strength for ordinary concrete (Equation (2)), the relationship between unconfined compressive strength and the splitting strength of pavement base material can be obtained.An analysis of the test results revealed the relationship between unconfined compressive strength and splitting strength, as shown in After fitting the test data with the power function and linear function, Equations (3) and (4) were obtained, respectively.The appearance of the specimens was recorded in 0, 5, 15, and 30 freeze–thaw cycles, as shown in As shown in The changes in the weights of the specimens under different freeze–thaw cycles are shown in Dc, is as shown in Equation (5). Pn is the unconfined compressive strength of the specimens under n freeze–thaw cycles (MPa), and P0 is the unconfined compressive strength of the specimens before freeze–thawing (MPa).According to reference , the uncFreeze–thaw cycle failure is a physical change process of the pore water in the specimens under the alternating action of high and low temperatures. During freezing, pore water transforms into ice under the action of low temperatures, resulting in ~9% volume expansion. This leads to a certain frost-heaving force on the capillary wall. If the frost-heaving force is greater than the ultimate tensile strength of the capillary wall, the wall will break and new microcracks will form. Under the repeated action of high and low temperatures, the structure of cement paste is gradually destroyed, the width and number of cracks increase, and the pore structure of the specimen deteriorates gradually. This deterioration is characterized by the change in the weights of the specimens and the decrease in their bearing capacity.The test results show that the addition of slag can effectively improve the frost resistance of the specimens because when slag replaces a part of the 0–4.75 mm macadam, many closed pores are formed in the slag under the microaggregate effect of cement and fly ash and the secondary hydration reaction. These closed pores resist a part of the seepage pressure, effectively reducing the invasion speed of water, damage caused by the frost-heaving force, and osmotic pressure on the specimens. Thus, the presence of the closed pores significantly improves the frost resistance of the specimens. With an increase in the cement content, the frost resistance of the specimens also gradually improves. The main reason for improvement is that with increasing cement content, the amount of dense gel materials such as C–S–H increases, the density and cohesive force of the interface transition zone of the specimens are improved, and the damage caused by the frost-heaving force and seepage pressure to the specimens is reduced.The reflection and refraction of ultrasonic waves on the interface of different media can be examined to detect the compactness of specimens. In the test, ultrasonic testing was performed on the specimens on the 7th day, and the measured sound waves were converted into spectral images, as shown in From the fitting results shown in Under the action of freeze–thaw cycles, the cumulative damage caused to the specimens will inevitably cause the development of cracks. Internal cracks of the specimens can absorb and dissipate the sound-wave propagation energy. Based on principle of ultrasonic wave propagation, ultrasonic rays will bypass the defect area and travel along the path corresponding to minimum travel time. Therefore, ultrasonic testing can be used to detect the internal defects of the specimens. Attenuation occurs when ultrasonic waves pass through these defects, resulting in a decrease in wave velocity . TherefoEr, is generally used [D is introduced to evaluate the damage parameters. The initial damage value D of the default specimens is 0. The equations for Er and D are as follows:Er is the relative dynamic modulus of elasticity (MPa), En is the dynamic elastic modulus of the specimens after the nth freeze–thaw cycles (MPa), E0 is the initial dynamic modulus of elasticity of the specimens (MPa), Vn is the longitudinal wave velocity after the nth freeze–thaw cycles (km/s), V0 is the initial longitudinal wave velocity of the specimens (km/s), L is the initial length of the specimens (mm), Tn is the sound time of the specimens after the nth freeze–thaw cycles, and T0 is the initial sound of the specimens.With an increase in the number of freeze–thaw cycles, the cracks in the specimens grow and expand rapidly, resulting in a change in the path of ultrasonic waves through the specimens. This change is directly indicated by the change in the ultrasonic sound time and wave velocity. To describe the degree of damage caused to the specimens by the freeze–thaw cycles, the relative dynamic elastic modulus, lly used ,35,36. FD and the number of freeze–thaw cycles n can be obtained using Equations (7) and (8), as shown in The relation between damage factor D, of the specimens increases with an increase in the number of freeze–thaw cycles. The damage caused to the specimens without slag is greater than that caused to samples with slag, and the freeze–thaw damage with low cement content is larger as compared to samples with high cement content. After 30 freeze–thaw cycles, the damage factors of 5-SR-25, 5-SR-50, 5-SR-75, and 5-SR-100 samples were 0.6599, 0.2056, 0.2686, and 0.2639, respectively. Compared with the 5-SR-0 sample, the freeze–thaw damage of 5-SR-25, 5-SR-50, 5-SR-75, and 5-SR-100 specimens decreased by 0.114, 0.569, 0.506, and 0.480, respectively. For a given cement content, with an increase in the slag replacement rate, the freeze–thaw damage of specimens decreased at first and then increased, and the freeze–thaw damage of 5-LZ-50 was the least. The proper amount of slag can form a relatively close accumulation system with cement, fly ash, and macadam, thereby increasing the compactness of the specimens. However, when the slag replacement rate was 50%, the appropriate and uniformly distributed closed pores resist a part of the water seepage pressure, effectively reducing the invasion speed of water, the damage of frost-heaving force, and osmotic pressure on the specimens. However, with the further increase in slag replacement rate, excessive closed pores will accelerate the connection and formation of capillaries, promote the invasion of water, increase the frost-heaving force caused by water condensation into ice, and reduce the frost resistance of the specimens. With an increase in cement content, the damage factor of the specimens decreases gradually. The main reason is that with an increase in cement content, the contents of C–S–H and other gel materials generated by the secondary hydration reaction in the specimens increase, thereby increasing the density of the interface transition zone, improving the stability and strength of the specimen, restraining the development and expansion of microcracks, and enhancing the frost resistance of the specimens.D is similar to the unconfined compressive strength, Dc. Reference [Er, and the relative compressive strength is similar to the power function. Therefore, Equation (9) is introduced to evaluate the relationship between the relative dynamic elastic modulus and the relative compressive strength of the specimens.eference  shows tha and b are obtained by nonlinear regression analysis.In the equation, the values of According to the fitting results shown in (1)Macadam of 0–4.75 mm was replaced by 0–4.75 mm slag, which not only reduced the consumption of macadam and the pollution of slag caused to the environment but also significantly increased the frost resistance of the mixture.(2)D, were established. According to the relationship models, ultrasonic nondestructive testing was used to detect the unconfined compressive strength and freeze–thaw damage degree of the mixture.Based on the principles of ultrasonic testing, the relationship models between ultrasonic wave amplitude and unconfined compressive strength, freeze–thaw damage factor Slag and macadam stabilized with cement and fly ash mixture is a new type of pavement base material. The main road performance indexes of the material were studied through mechanical, frost resistance, and ultrasonic tests. The results show that the mechanical and frost resistance properties of the mixture meet the requirements of Chinese pavement base specifications. Compared with previous studies, the paper mainly has the following two innovations:(1)The fatigue and shrinkage performance of the mixture are not tested.(2)The meso-finite element model of mixture is not established.(3)A machine learning algorithm is not used to predict the strength and freeze–thaw damage degree of mixture.However, this study also has the following deficiencies, which are also the focus of future research:Therefore, we will gradually improve these deficiencies in future studies.(1)The optimum water content of the specimens increases, and the maximum dry density decreases with an increase in the slag replacement rate. Slag has an adverse effect on the unconfined compressive strength of the specimens. However, with extension of the curing age, the adverse effect of slag on the unconfined compressive strength of the specimens decreases gradually. With an increase in the cement content, the unconfined compressive strength of the specimens increases.(2)The appearance of the specimens worsens, and the unconfined compressive strength decreases gradually with the increase of freeze–thaw cycles. The unconfined compressive strength loss of the specimens decreases at first and then increases with the increase of slag replacement rate, and the unconfined compressive strength loss decreases with the increase of cement content. When the cement content is 5% and the slag replacement rate is 50%, the unconfined compressive strength loss of the specimen is minimal.(3)v, relative dynamic elastic modulus Er, and damage factor D were proposed. The strength attenuation model between relative dynamic elastic modulus and relative compressive strength under freeze–thaw cycles was established to evaluate the frost resistance of the mixture.According to the test results, the relationship model between compressive strength and splitting strength of the mixture was established by linear function and power function regression analyses. The relationship model between unconfined compressive strength at 7 days and ultrasonic amplitude was established. The formulas between ultrasonic wave velocity (4)The comprehensive test results show that the slag replacement rate is recommended to be ~50%, and the mixture has good mechanical and frost resistance properties. When the cement content is 5%, the mixture can meet the technical requirements of expressway and first-class highway pavement base in China.According to the mechanical, frost resistance, and ultrasonic test results of slag and macadam stabilized with cement and fly ash mixture, the following conclusions are drawn:


In this paper, the effects of the structural parameters of magnetic-knitted fabric on human skin microcirculation (HSM) were studied in relation to magnetic polypropylene yarn, which was used as raw material. Three experimental factors were designed: the magnetic powder content of polypropylene, the feeding ratio of magnetic polypropylene (MP) and graphene viscous (GV), and stitch. Twelve pieces of seamless knitted fabric were prepared according to the comprehensive experimental design method. The BIV angiography was used to proceed with an HSM test of about 12 pieces of seamless knitted fabric. The results show the following: The magnetic powder content of polypropylene has the greatest influence on the blood flow promotion multiples of skin–blood microcirculation, followed by the feeding ratio of MP and GV, while stitch has the least influence. When the plating yarn feeding ratio was 100:0, the magnetic powder content of polypropylene was 50%, and the stitch was 1 + 1 false rib, meaning that the fabric could promote HSM more efficiently. This is compared against the common polypropylene knitted fabric, where the blood flow promotion multiples increased by 9.87%. The purpose of this study was to explore the structural parameters of magnetic polypropylene-knitted fabric that has a better effect on promoting HSM, and to provide a reference for the development of functional health-knitted fabrics. With the development of the social economy and the continuous innovation of science and technology, people are increasingly exposed to more electronic products that produce substantial electromagnetic radiation . There iMicrocirculation mainly plays the role of material exchange between tissues and blood microcirculation that exists between the arterioles and venules of microvessels ,11. The Magnetic fibers are divided into magnetic non-textile and magnetic textile fibers. At present, the preparation methods of magnetic fiber include the fiber surface coating method, fiber physical and chemical modification, the blending spin method, the 3D printing method, the impregnation method, the position synthesis method, and the electroplating method . Among tIn 2004, Qi et al.  made a mIn this study, magnetic polypropylene (MP) yarn and graphene viscous (GV) yarn were used to design a four-level face yarn ratio and a three-level magnetic powder content of polypropylene and stitch. The 12 seamless knitted fabric samples were designed and woven according to the comprehensive experimental design method. The influences of various factors on human skin microcirculation (HSM) were analyzed by an orthogonal experiment, and the horizontal combination of process parameters with better performance was obtained, providing a reference value for the development of magnetic health care seamless knitting products that are suitable for winter, and thus greatly promoting HSM and skin–blood flow velocity.Considering that magnetic strength is directly related to magnetic powder content, polypropylene yarn was purchased directly from Beijing Baiquan Chemical Fiber Factory ; MP fiber was prepared by the blending spin method. Considering the poor moisture absorption of the polypropylene fibers, the production cost, and the heat retention, as well as the antistatic behavior of winter clothing, GV yarn was selected. Meanwhile, Nylon/spandex-coated yarn with better elasticity was chosen. MP yarn and GV yarn were used as raw materials for face yarn and the nylon/spandex coated yarn [22.2dtex(20D) nylon yarn /77.8dtex(70D) spandex yarn] were used as raw materials for lining yarn. The raw materials and specifications of face yarn are shown in This paper studies the effects of three factors on magnetic powder content: polypropylene, the feeding ratio of MP and GV, and stitch. The sample scheme was designed by an orthogonal experiment. The specific factor levels are shown in This paper designed a 4-level face yarn ratio and a 3-level magnetic powder content of polypropylene and stitch. The sample was knitted with an SM8-TOP2S seamless knitting machine and 8-way yarn feeding. The MP and GV were reasonably set at a feeding ratio of: 8-way MP+0-way GV, 100:0; 6-way MP+2-way GV, 75:25; 4-way MP+4-way GV, 50:50; 2-way MP+6-way GV, 25:75. Three kinds of stitches were selected: the weft plain stitch weave with good elongation in vertical and horizontal direction in seamless knitting; 1 + 1 false rib; and 1 + 3 false rib, which enabled the fabric to be warmer and thicker. In this paper, the orthogonal experimental design of the partial addition method was selected to carry out a comprehensive experiment on a 4-level face yarn ratio, a 3-level magnetic powder content of polypropylene, and a stitch, totaling 12 groups of samples. The weaving scheme of the sample fabric is shown in Laboratory equipment: The BVI Angiography provided by Shenzhen Shengqiang Technology Co., Ltd. .The blood flow imaging function of the BVI Angiography instrument can be used to test the living tissue with an 18 cm × 12 cm test area, and the change in blood perfusion in living tissue can be observed in real time. It is suitable for surgical wound evaluation, cerebral blood flow detection, burn recovery diagnosis, and other fields.The BVI Angiography instrument’s working principle is as follows: Use the principle of laser speckle imaging when the host sends a laser to the surface of the object. Due to the roughness of the tissue surface, the incident light produced backscatter and random interference upon the imaging surface, thus forming speckle with varying degrees of light and dark. After the image processing software system connected to the computer by the BVI angiography device is converted, we saw the image of the blood vessels on the tissue surface, and obtained the value of the blood perfusion of the blood vessels on the tissue’s surface. The data obtained from the test cannot directly obtain the exact value of blood flow, but they can directly reflect the change in blood flow perfusion volume of the tested tissue.Experimental environment: Ambient temperature is 24~26 °C, relative humidity is 40~60%, indoor lighting, no wind, avoid direct sunlight.Experimental requirements: Before the experiment, the sample was put in a standard atmospheric environment for testing (damp) for 24 h. Two test points were marked for subjects in advance. The test points were kept at the same position to avoid any influence on the test results. Subjects were not allowed to consume strong tea, coffee, milk tea, or food containing polyphenols 2 h before the formal test. They sat in the test environment for more than 30 min to avoid the influence of biological physiological changes on the test results. After the subject relaxed, the non-dominant hand was placed on the experimental platform and covered with cotton cloth for more than 15 min to avoid changes in the blood microcirculation of the biological body caused by exercise, which may affect the test results. During the test, the subject’s left arm should be kept quiet in the laboratory, and the subject’s left arm should be relaxed and kept still. The sitting position should not cause any pressure to be applied on the left arm. After obtaining the blood perfusion, the subject’s left arm could move slightly to avoid paralysis of the left arm caused by being placed on the experimental platform for an extended duration.Subject condition: To avoid the influence of individual differences on the test results, ten healthy female adults, aged 22–26, 155–165 cm in height, and 45–70 kg in weight, without diabetes, somatosensory disorders, hypertension, cardiovascular diseases, and other diseases, were selected .2 were selected, while the test position and test points were the forearm of the subjects’ non-dominant hand, as shown in Skin microcirculation test position: Combined with the feasibility of the experiment, the selected test points should avoid superficial veins visible on the skin’s surface of the human body; the distance from the wrist was no less than 5 cm and the distance from the elbow fossa was no less than 2.5 cm. The test points with a skin area of about 1.5 cmEstablishment of fabric sample test scheme: Determination of test scheme of fabric-perforated, width, and covered time.Sample selection: MP-10 Weft plain stitch knitted fabric was used at test point 1 and MP-0 Weft plain stitch knitted fabric was used at test point 2.In order to make the test results more accurate and reduce the influence of the test results, three factors were considered: the fabric-perforated test scheme, the fabric width, and the fabric covered time. Three perforated test schemes were designed: (1) the sample did not perforate; (2) the sample was not covered or perforated; (3) The sample was perforated and covered. When covering the sample, the test point covered the round sample with a diameter of 2.2 cm. Four different coverage sample widths were designed: 6 cm, 8 cm, 10 cm, and 12 cm. Five different sample covered time schemes were designed: 5 min, 10 min, 15 min, 20 min, and 25 min. According to the principle of single variable, 10 healthy females were tested in turns for HSM blood perfusion. The test results showed that the blood flow promotion multiples were better when the sample was perforated and covered, as well as when the width of the covered sample was 10 cm and the time of the covered sample was 20 min.Sample size: The width of the sample was 10 cm and the length of test point 1 near the wrist was 19–23 cm. The length of test point 2 near the elbow was 23–27 cm, and Velcro was 4 cm to ensure that the sample was completely wrapped around the forearm and the sample size could be adjusted appropriately. The sample was adopted under the perforated and covered test scheme. When covering the sample, the test point covered a round sample with a diameter of 2.2 cm. The extended forearm status and blood flow imaging of subjects’ non-dominant hand are shown in The subject adapted to the laboratory environment according to the above requirements for preparation before the test, and we tried to adjust their physiology to a balanced state;The BVI Angiograph was turned on and the vertical distance between the instrument host and the forearm test position was adjusted according to the red laser beam emitted by the instrument until the “Invalid” on the computer software page polypropylene appeared as “good”;Blood perfusion original value tested: Subjects’ non-dominant forearm was placed on the experimental platform for 15 min and remained in a relatively static state. The test software selection function was used according to participants in advance of the test point mark, selected, and test point 1 and 2 values of dynamic perfusion were tested; 100 s of blood perfusion amounted to a relatively stable area of more than 20 s. The test software automatically calculated the average of the blood perfusion in the area;The blood perfusion test after covering the sample: The steps of the original blood perfusion test were repeated after covering the fabric sample for 20 min, and the average blood perfusion amount after covering the sample at test points 1 and 2 was obtained;Subjects should sit still for at least 10 min after the end of the tests.Using the BVI Angiography test coverage samples before and after the local blood flow perfusion, the cover sample was calculated before and after the blood flow velocity ratio. Then, the blood flow promotion multiple of the covered sample was obtained. The effects of the feeding ratio of MP and GV, and stitch on HSM, were studied. The influences of various factors on HSM were analyzed by an orthogonal experiment, and the horizontal combination of fabric structural parameters with better performance was obtained.The calculation method of blood flow promotion multiple was based on the laser Doppler flowmetry (LDF) detection method . The calF is the blood flow velocity ratio; F0 is the original blood flow velocity ratio; hF is the ratio of blood velocity after covering the sample; f1 is the blood perfusion at test point 1; f2 is the blood perfusion at test point 2; N is the blood flow promotion multiple after covering the sample.Twelve pieces of seamless knitted fabric were used to test skin–blood microcirculation, and the test results are shown in In order to intuitively observe the influence of 12 pieces of seamless knitted fabric on the blood flow promotion multiples of skin–blood microcirculation in 10 healthy females, as well as the test results of the skin–blood microcirculation of the 12 pieces of seamless knitted fabric, a trend chart showing the blood flow promotion multiples of skin–blood microcirculation was made .It can be seen from According to the results in This experiment selected MP yarn and GV yarn as materials and chose three important factors affecting the performance of seamless knitted fabric: the magnetic powder content of polypropylene, the feeding ratio of MP and GV, and stitch. Twelve samples were prepared. References to the LDF detection method and BVI Angiography were made to test the influence of each sample on the HSM of 10 subjects. Finally, the sample with better performance was evaluated by the orthogonal test design with the partial addition method, and the structural parameters of the sample were obtained. The analysis of multiples of skin–blood microcirculation showed the magnetic powder content of polypropylene, followed by the face yarn ratio. Stitch had the least influence. When the face yarn ratio was 100:0, the magnetic powder content of polypropylene was 50%, and the stitch was 1 + 1 false rib, meaning the fabric could promote HSM better than the common polypropylene knitted fabric, in which the blood flow promotion multiples increased by 9.87%. The optimal sample scheme of the face yarn ratio was 25:75, the magnetic powder content of the polypropylene was 50%, and the stitch was weft plain stitch. The purpose of this study was to explore the structural parameters of MP fiber-knitted fabrics that have a better effect on promoting HSM so as to develop textiles that can promote the microcirculation of human skin with excellent performance. Additionally, this study provides a clear reference basis for the application of magnetic health care textiles in the adjuvant treatment of chronic diseases such as scapulohumeral periarthritis.


Studies of the dental status of children with cerebral palsy (CP) indicate a high prevalence and intensity of damage to the hard tissues of the teeth. The risk of developing dental diseases is known to increase significantly as the severity of neurological symptoms increase. The purpose of the study was to assess the incidence of dental caries using the International Caries Detection and Assessment System (ICDAS II) criteria in children with organic diseases of the nervous system depending on the severity of motor impairment. A number of 122 children (mean age 8.8±3.7 years) with spastic forms of cerebral palsy were examined. They were divided into groups according to the Gross Motor Function Classification System – Expanded & Revised (GMFCS-ER). All patients underwent a neurological examination, and the state of dental caries was determined using the ICDAS II criteria. In children with cerebral palsy, lesions of the occlusal surfaces of the teeth predominate, lesions of the proximal surfaces appeared to be three times less, but more than three times higher than in healthy children. Higher intensity of the carious process and the frequency of deep cavities are observed in children with cerebral palsy with severe motor impairment, according to GMFCS-ER. Establishing the features of caries development in children with cerebral palsy depending on the severity of neurological symptoms according to the ICDAS II system is an essential factor in determining the direction of preventive measures that should be taken for this group of children. Nowadays, infantile cerebral paralysis (ICP) or cerebral palsy (CP) remains one of the most common neurological pathologies, most often resulting in the disability of patients under 18 . One of Examination of the dental status of children with CP is indicative of a wide occurrence and intensity of lesions of their hard dental and periodontal tissues. Some studies have demonstrated that the risk of development of dental diseases increases reliably with the increase of manifestation of neurological symptoms –15. ThisConsidering the high occurrence of dental disorders, difficulty to implement traditional therapeutic and preventive measures, and the considerable effect of dental pathology on the quality of life of children with organic lesions of the nervous system, detection of caries lesions in this group of children depending on the intensity of motor impairment remains an important issue.Therefore, the purpose of our study was to assess the incidence of dental caries using the International Caries Detection and Assessment System (ICDAS II) criteria in children with organic diseases of the nervous system depending on the severity of motor impairment.A number of 122 children (mean age 8.8±3.7 years) with spastic types of cerebral palsy were examined at the Regional Center of Medical-Social Rehabilitation of Children with Organic Lesions of the Nervous System Chernivtsi, Ukraine. The children with CP were divided into groups according to the Gross Motor Function Classification System – Expanded & Revised (GMFCS-ER) : the firCaries dental lesions were assessed in all the children using the International Caries Detection and Assessment System (ICDAS II) . ICDAS IAccording to the criteria, code 0 (ICDAS=0) corresponds to an intact tooth, 1 and 2 characterize initial lesions of the dental enamel , and 3 corresponds to visible lesions of the dental enamel . Codes 4, 5 and 6 represent carious dental lesions. The criteria are developed considering the fact that every point corresponds to a specific degree of the lesion (intensity) of the hard dental tissues, and a direct correlation between points and intensity of lesion determined by pathomorphological methods is evidenced –21.We assessed the absolute and relative number of teeth possessing different codes according to ICDAS II in different groups of children, as well as the absolute and relative amount of dental surfaces among all the surfaces examined, which enables to determine prevailing caries location among the group of children involved into the study, and, to some extent, make recommendations concerning therapeutic-preventive measures. The data obtained were statistically processed by means of the applied programs Microsoft Excel 2010®, Biostat®, Statistika® 7.0, and Student’s t-test (paired and unpaired). The majority of the children examined were diagnosed with spastic forms of CP: 40 (32.8%) children had spastic diplegia, 25 (20.5%) had a hemiparetic form, 6 (4.9%) had spastic triparesis, 34 (27.9%) had spastic tetraparesis; hyperkinesis was diagnosed in 10 children (8.2%) and ataxic syndrome in 7 (5.7%) children.Dental examination of children with organic nervous system lesions found that caries occurrence was 100%, contrary to healthy children from the comparison group where this index was 68.7%. An average value of caries intensity by the dt, DMF+dt, and DMF indices in children with CP was 6.27±1.19, which is 2.3 times higher than healthy children .th group, 1.69% (It should be noted that children with CP had a rather high percentage of extracted teeth: 1.11% (7 teeth) in children from the third group, 1.77%  among all the examined teeth in children with CP and 43 (2.3%) in somatically healthy children. Such an amount of treated teeth in children with CP is not indicative of proper oral hygiene since reliably higher indices of deep carious with their complications were found in children with CP with intense motor impairments, according to the data of our study.Analysis of caries lesions according to the ICDAS II criteria in children with CP has demonstrated the following:•Code 0 was registered in 73.2% of cases among all the examined teeth. In children from the control group, code 0 was registered in 87.97% of cases, which corresponds to the difference between caries occurrence in the patients with CP and without it; •Code 1 was not practically registered in the groups of children with CP and practically healthy children. It might be associated with certain difficulties in examining sick children and finding inconsiderable damage of the normal condition of the dental enamel; •Code 2 was found in 1.43±1.66% of all the examined teeth of children with CP compared to 1.32±0.72% in the control group (p>0.05);•There were no reliable differences found in the percentage of teeth with codes 3 and 4 between children from the control group and those with CP: code 3 was found in 1.72±1.41% of children with CP compared to 2.02±0.66% in healthy ones;•Code 4 was found in 4.49±1.54% in children with CP compared to 2.83±0.83% in the control group. Though in children with organic lesions of the nervous system, the percentage of teeth with code 4 was 3.2 times higher as compared to the similar index in healthy children, which is indicative of a tendency to a higher occurrence of hidden carious cavities and, thus, to progressing carious process in this group of patients . •Regarding codes 5 and 6, we found reliable differences between sick and practically healthy children: code 5 was 3.8 times more frequent in children with CP compared to healthy ones – 5.91±1.84% vs. 1.58±0.92%; respectively (p<0.05). Code 6 was 7.5 times more frequent in children with CP compared to healthy children . Such correlations remained valid during all occlusion periods , and theCode 4 was found to be reliably higher (2.3 times as much) in children from the third group compared to the control group . In children from the fourth and fifth groups who suffered from severe motor impairment, code 5 was found in a reliably higher percentage of children in comparison with healthy children . The same was applicable for code 6 , which is indicative of a considerable occurrence of extensive caries of the dentin in these groups of patients. Differences between high codes in children from the main and control groups are registered mostly at the expense of those children who suffer from severe motor impairment.Analysis of differences among children from different groups by the intensity of motor impairment found a reliable difference between code 6 in the fifth group of patients with CP and the first group with inconsiderable motor impairment: code 6 was 4.2 times more frequent in patients from the fifth group in comparison with patients from the first group . It can be indicative of increased intensity of an active carious process with the formation of extensive carious cavities closely correlated with motor impairment in children with CP.Similar tendencies were observed in children with temporary, transitional, and permanent dentition –5. An exDentine caries prevails considerably in children with transitional dentition . SuperfiIn permanent dentition, the teeth with code 4 prevailed. Though, with the increase of the degree of motor impairment functions , code 4 was gradually substituted by codes 5 and 6 (visible dentine caries), which was indicative of increased severity of caries in children with deterioration of their motor activity .Analysis of caries structure on the surface of non-filled teeth in children with CP  determinIn children with CP, approximal caries were found in 4.94% of the general amount of the examined surfaces of the teeth. Analysis of caries on the approximal surfaces found that the highest percentage of this index was found among children with CP and intensive motor impairment: 6.12% in the fourth group and 6.85% in the fifth group. Approximal surfaces of the molars were afflicted most often, which is explained by the practically complete absence of interdental hygiene of the examined children. Code 4 was most often registered on the approximal surfaces (hidden caries), codes 5 and 6 on the grinding surfaces . Despite this, they were not less frequent than the occurrence of approximal caries. High occurrence of caries on the approximal surfaces is known to be associated with peculiarities of the anatomical structure, accumulation of food debris and unsatisfactory oral hygiene, formation of aggressive dental plaque in the natural depressions of teeth, intake of refined carbohydrates, influence of negative factors of the underlying disease, and longer periods of hypomineralization in comparison with the smooth surfaces of the teeth –30.In some cases, the carious lesion was associated with the formation of defects on the vestibular and oral surfaces of the teeth in children with CP, which was 5 times higher than that of occurrence of those defects in practically healthy children – 104 children (3.5%) vs. 13 (0.7%) among all the examined teeth, respectively. Depth of vestibular defects was different: in some cases, occlusive and vestibular cavities remained isolated one from another; in some of them, rapid destruction of hillocks, consolidation of cavities, and enamel loss on the greater part of the occlusive and smooth surfaces occurred, followed by further destruction of the dentin, development of caries complications with complete loss of the crown, especially in children with severe motor impairments.Thus, lesions of the occlusive surfaces of the teeth prevail in children with CP ; yet, lesions of the approximal surfaces were three times less. However, this index was increased by three times compared to healthy children. The high occurrence of occlusive caries in temporary dentition can be explained by quick destruction of the grinding surface of the molars at the expense of its hypomineralization during intrauterine development of a child caused by the factors stipulating the formation of neurological pathology. Prevailing of occlusive caries over approximal ones in the transitional and permanent dentition can be explained by the lack of close space between teeth at the expense of incomplete formation of dentition. Smooth surfaces of the teeth are afflicted in the areas of physiological hypomineralization, and in the area of the neonatal line in particular, in case proper oral hygiene is lacking.Finding peculiarities of caries development in children with CP depending on the severity of neurological symptoms is an important factor in order to determine the direction of preventive measures for this group of children.We found a higher frequency of caries process among children with CP and severe motor impairment. Surfaces of the teeth with deep caries (codes 5 and 6 according to ICDAS II) are more often found among children with CP and severe motor impairments. Occlusive caries prevails among both children with CP and somatically healthy ones, though lesions are found on all the surfaces of the teeth.The approval for this study was obtained from the Ethics Committee of the HSEEU Bukovinian State Medical University, Ukraine ,Written informed consent was obtained from the patient’s parents.The authors declare that there is no conflict of interest.


Backgraund: Acromegaly is a multi-organ disabling disease, the effectiveness of treatment of which directly depends on timely diagnosis. Latent course and delayed diagnosis increase the exposure of pathological hypersecretion of growth hormone and insulin-like growth factor-1, contributing to the development of irreversible systemic and metabolic changes in the body that negatively affect survival.Aims: The aim of the study was to clinically test a comprehensive diagnostic approach using selective screening to detect cases of acromegaly in patients with combined somatic diseases.Materials and methods: The diagnostic search algorithm included a 2-stage questionnaire, expert assessment of the clinical status, laboratory and instrumental examination. The inpatient examination included the use of additional laboratory and instrumental methods and expert evaluation of the results obtained by filling out a doctor’s questionnaire. When the score was higher than 18 points, a more specific examination was performed: double determination of the insulin-like growth factor-1 level, oral glucose tolerance test with determination of the nadir of growth hormone value, and MRI of the brain with contrast enhancement. The diagnosis of acromegaly was made on the basis of personal data, expert assessment of the clinical status, results of laboratory and instrumental examinations.Results: A survey of 1249 patients with combined systemic and metabolic disorders conducted using the point system allowed us to suspect acromegaly in 367 patients (29.4%), who were offered further examination. The majority of patients were previously seen by specialists for diabetes mellitus (79.3%) or thyroid pathology (10%). In the result of inpatient examination of 329 patients, 35 (10.6%) patients showed an increase in the blood level of IGF-I. In 19 patients, a persistent increase in the level of IGF-I was combined with the absence of GH suppression of less than 0.4 ng/ml against the background of glucose load. During MRI in 9 patients, pituitary adenoma was detected (in 2 — microadenoma and 7 — macroadenoma).Conclusions: As a result of the study, among the group of 1249 patients (mean age 58±13 years) with the presence of concomitant diseases, 9 newly identified patients with acromegaly were found who were prescribed adequate treatment. The introduction of selective screening technology into the practice of an endocrinologist will improve the effectiveness of diagnostic search for patients with acromegaly, more accurately assess the prevalence of the disease in Russia and the need for specialized medical care. Acromegaly is a severe neuroendocrine disease that steadily leads to a decrease in the quality and duration of life of patients, which is a consequence of the cumulative negative effects of excessive concentrations of growth hormone (GH) on the human body. In the absence of appropriate treatment, the mortality rate of patients with acromegaly is 2-4 times higher than the average in the population. Independent predictors of untimely death include oncological diseases, cardiovascular disorders, arterial hypertension, diabetes mellitus, and an active stage long duration [1-5].With the consideration of the multiplicity of clinical and pathomorphological options of the course of acromegaly, it should be noted that external somatic disease manifestations, as a rule, are not only delayed, but also not always pronounced. According to J. W. Hong et al., only 35% of patients have definitive changes in the facial skeleton, an increase in the size of soft tissues, hands, and feet . More ofIn addition to skeletal changes and mass effect, the most common clinical manifestations of acromegaly are arterial hypertension; cardiomyopathy, manifested by concentric myocardial hypertrophy with the development of diastolic dysfunction, valvular insufficiency and cardiac failure; respiratory failure due to obstructive sleep apnea, pulmonary emphysema and pneumosclerosis; nodular (diffuse-nodular) goiter; polyposis and intestinal tract diverticulosis. The leading issue in acromegaly is a violation of carbohydrate metabolism, the degree of incidence of which in the older age group reaches 50-60%. The prevalence of diabetes mellitus, nodular goiter, arterial hypertension, and cardiomyopathy correlates with the duration of the active stage of acromegaly [12-16]. According to F. Golkowski et al., already 3 years after the debut of acromegaly, one of the above complications is detected .In addition, patients with acromegaly have 3.4 times greater risk of developing malignancies compared to the general population. The high incidence of colorectal cancer, breast and thyroid cancer has been proven. Oftimes, patients have multifocal tumors of various tissues. Thus, it was noted that the greatest number of extrapituitary neoplasias in acromegaly is observed against the background of symptomatic diabetes mellitus, the main pathogenetic links of which ( hyperinsulinemia and insulin resistance) increase cancer mortality rates [18-21].Thus, the cumulative pathological effect of autonomous hyper-GР on the body leads to the development of multiple morphofunctional changes that contribute to early disability and untimely death of patients with acromegaly. The implication is that the disease early diagnosis and appropriate treatment, careful monitoring of possible complications play a crucial role in the optimal management of such patients and improving their survival [22-24].According to international registries, the prevalence of acromegaly varies in different countries from 28 to 137 cases per 1 million population and depends on the age of debut, environmental conditions of residence, awareness of general practitioners and the quality of the prophylactic medical examination. In the Russian registry in 2020, there are 4114 patients with acromegaly, which corresponds to an average prevalence of 35.6 cases per 1 million population  [25–33].On average, the onset of the disease occurs in the IV-V decades of life, when, on the one hand, a pathogenic pool of natural and induced mutations accumulates in the cells, and on the other hand, involutional changes begin to prevail in the body, leading to the development of multisystemic dystrophic and neoplastic processes. An additional contribution to the aetiopathogenesis of acromegaly is made by poor environmental living conditions. So, according to the results of the investigation, S. Cannavo et al., the prevalence of acromegaly in environmentally pristine and industrially polluted areas of Italy was 26 and 210 patients per 1 million population, respectively, which confirms the mutagenic involvement of adverse environmental factors .The incidence and prevalence of acromegaly increase significantly with age. According to T. Burton et al., the incidence of acromegaly averages 11 new cases a year per 1 million population in the United States. Thus, in the age group under 17 years, this figure was 3-8 cases per 1 million, while in people over 65 years of age, the incidence increased to 9-18 cases per 1 million of the population. A similar trend persists when assessing the prevalence of this pathology: with an average of 78 cases per 1 million population, the prevalence of acromegaly in the groups of people under 17 years of age and over 65 years of age was 29-37 and 148-182 cases per 1 million population, respectively .At the same time, it should be mentioned that: the registration of patients by the number of ambulations does not correspond to the real epidemiological situation in the region, which, in our opinion, is due to several reasons. Firstly, due to the lack of effective medical control, only a small part of patients go to medical institutions. Secondly, the awareness of doctors of other specialties regarding the clinical symptoms of acromegaly is not always at the adequate level. And thirdly, highly sensitive methods of diagnosing the disease are not everywhere applied. Significant progress in the detection of this pathology is associated with the introduction into clinical practice of methods for determining IGF-1, the increased content of which in the blood is a priority when establishing diagnosis .It is noted in T.J. Reid et al. paper that over the past 25 years, the efficiency of detecting acromegaly has not undergone significant changes. In the majority of patients, the diagnosis is made at the at advanced stage of illness with a deliberately limited therapeutic maneuver and a negative prognosis . The tarAll of the above indicates that the quality and life expectancy of patients with acromegaly depends to a large extent on the timely diagnosis. A paradoxical situation has arisen when the current techniques of treatment that provide patients with a full and fruitful life cannot be completely used due to the low efficiency of diagnostic services. For many unrecognized patients, the question of when to get access to appropriate treatment has become vital. The existing urgent problem of timely diagnosis of acromegaly initiated the development of programs for active mass or selective population screening, the specific characteristics and the first results of which are presented below.Mass screening to identify patients with acromegaly includes the following programsSelective screening is aimed at identifying acromegaly among patients with definitive associated diseases:Regarding the preliminary results of the ongoing studies, it can be noted that any form of active updating of national registries deserves respect, since they contribute to the identification of an additional number of new patients and the improvement of diagnostic searching techniques. According to P.W. Rosario et al., even the primary introduction of symptomatic questionnaires into outpatient practice allowed for better diagnosis and an increase in the prevalence of acromegaly to 290 cases per million population .Due to the developed computer programs for the analysis of the geometric arrangement of sign points on photographic images of the face, it has become possible to significantly increase the percentage of detected patients in comparison with the expert opinion, especially with a mild form of acromegaly. According to R.E. Miller et al., the diagnostic accuracy of mathematical processing of photographs is 86%, while medical diagnostics is only 26%. Similar investigations have shown that the diagnostic accuracy of computer models is 72% compared with expert diagnostics (63%) and conclusions of general practitioners (42%) [41–44]. The same applies to studying the possibilities of diagnosing the disease by assessing the acoustic characteristics of the voice in patients with acromegaly, which is characterized in a hoarse and low sound . The preProjects to identify acromegaly among patients with impaired carbohydrate metabolism have been successful. In the investigation by P.W. Rosario et al., among 2270 patients with type 2 diabetes mellitus aged 20 to 70 years, 3 patients with acromegaly were identified, which made it possible to increase the prevalence of the disease to 480 cases per 1 million population. In K. Suda et al. paper, the examination of 317 patients of the older age group (60.7 ± 14.2 years) with type 2 diabetes mellitus and impaired glucose tolerance revealed 2 cases of acromegaly. It is significant that as the age of the surveyed cohort increases, the percentage of detection of acromegaly also increases, amounting to 0.13 and 0.63%, respectively. These data confirm that acromegaly is more common among patients of the older age group with impaired carbohydrate metabolism .The results of the mass screening (DETECT study) conducted by H.J. Schneider et al. in 2008 are widely known. Total determination of the IGF-1 level in 6773 outpatients (age group 18+) made it possible to identify 7 patients with acromegaly, which increased the prevalence of the disease to 1034 cases per million population . The disThe presented results of pilot epidemiological projects indicate that the actual prevalence of acromegaly is 15–20 times higher than officially registered, and, therefore, there is a large percentage of undiagnosed patients who do not receive specialized medical care. In this regard, early diagnosis of acromegaly remains an urgent public health problem, the solution of which will significantly increase the medical benefits efficacy.For this purpose, for the first time in Russia in 2013–2015 the non-interventional cross-sectional study ACROSCREEN was carried out, in which the diagnostic search for patients was carried out among patients with the associated diseases, most often found in acromegaly  goiter, arterial hypertension, myocardial hypertrophy, sleep apnea syndrome, polyps and diverticula of the gastrointestinal intestinal tract, uterine myoma, endometrial polyps, polycystic ovary syndrome, prostatic hyperplasia, osteoarthropathy, spinal deformities, carpal tunnel syndrome, oncology diseases in the medical history).The purpose of the study is to clinically test a diagnostic procedure for detecting cases of acromegaly in patients with associated somatic diseases.The study was observational. No interventions in routine clinical practice were performed within the study. Validation criteria For inclusion in the study, patients over the age of 18 years with somatic diseases associated with acromegaly were considered. By the exclusion criterion the patients with a previously confirmed diagnosis of acromegaly were meant.The search for study participants was carried out among 1249 patients who came for an appointment and were observed in connection with various diseases at the State Budgetary Healthcare Institution of the Endocrinological Dispensary of Moscow City Health Department and FSAEI HE of I.M. Sechenov First Moscow State Medical University of the Ministry of Health of the Russian Federation (Sechenov University). The patients who, according to the results of the questionnaire, scored 18 or more points and were included into the risk group, were offered further participation in the study.The duration of the study inclusion period was from December 2013 to September 2015.The study was conducted in 2 stages. At the first stage, a questionnaire survey of patients who came to the hospital and were observed there in connection with various diseases was carried out . Then th The laboratory and instrumental examination comprised the following:The content of IGF-1 in blood serum was determined by the chemiluminescence technique on an automatic analyzer Liaison  or by the immunoradiometric technique using the IGF-1 reagent kits produced by Immunotech (France), depending on the clinical facility. The GH level in the blood was determined using a solid phase chemiluminescence enzyme immunoassay on an automatic analyzer IMMULITE 2000 .Contrast-enhanced brain MRI was performed on the high-field tomograph (> 2 T) .Confirmation of the diagnosis of «acromegaly» was:The study was conducted in accordance with the ethical principles embodied in the Declaration of Helsinki . The DiaSampling size calculation principles: the study did not include a formal sampling size.Techniques for the Data Statistical Methods. In the investigated cohort, analyses were performed to assess the primary and secondary endpoints. The data from the questionnaires of patients and researchers were analyzed for the establishment or exclusion of the «acromegaly» diagnosis and compared with each other using the F-test statistic to determine statistically significant differences. Quantitative characteristics were assessed by the mean and standard deviation. Differences were considered statistically significant at a significance level of p <0.05 To determine the most pathognomonic subjective and sign symptoms of acromegaly, the logistic regression model and the discriminant analysis model were investigated. A stepwise algorithm  was used for discriminant analysis; roc statements were used to build a logistic regression model; roccontrast - for PROC LOGISTIC SAS procedure. The final model was assessed using a receiver operating characteristic curve (ROC) to determine the specificity of the model in order to distinguish between patients with acromegaly and patients who have no acromegaly.As a result of the questionnaire survey of 1249 patients, further participation in the study was offered to 367 (29.4%) patients who scored 18 points or more, of which 38 patients (10.4%) refused further participation. 329 patients (89.6%) have passed to the examination stage. The average age of the examined cohort was 58 ± 13 (46–72) years. The number of men - 54 (16%), women - 275 (84%).As a result of the initial processing of individual registration cards, it was revealed that the majority of patients were observed for a long time by various specialists for type 2 diabetes mellitus (79.3%) or thyroid pathology (10%). Among other diseases, cardiopathy (18.5%), osteoarthropathy (8.5%), neoplasms (22.8%), gynecological diseases (1.8%) were more common  An increase in the IGF-1 level above the age-appropriate normal value was observed in 35 patients (10.6%). The presence of «biochemical acromegaly», confirmed by a persistent increase in the IGF-1 level and the value of the GR nadir> 0.4 ng/ml, was detected in 19 cases. Of these - 17 patients underwent the contrast enhanced brain MRI, as a result of which a pituitary adenoma was detected in 9 patients (2 - microadenoma and 7 - macroadenoma). In the group of patients with identified GH-secreting pituitary adenoma, the mean IGF-1 value was 580 ± 336 ng/ml .In 8 patients with «biochemical acromegaly», no hormonally active adenoma was found intra or extrapituitary, which indicates the need for further case follow-up.So, as a result of a diagnostic search among patients with an average age of 58 ± 13 years and with the presence of concomitant diseases, 9 patients (2 men and 7 women) (age 58 ± 13 years) were newly diagnosed with «acromegaly». Previously, 5 of the newly diagnosed patients with acromegaly were treated for diabetes mellitus, 2 - for thyroid pathology, 1 - for osteoarthropathy and 1 - for cardiopathy. The duration of the disease prior the establishing diagnosis of acromegaly was 6.6 (1–16) years. The late diagnosis of the disease was indicated by the presence of somatic and metabolic complications, as well as the presence of a pituitary macroadenoma in the vast majority of patients. After detection of acromegaly, all patients were prescribed pathogenetic treatment .According to the results of the questionnaire, statistically significant signs that distinguish patients with acromegaly were: typical changes in appearance and an increase in the size of the limbs (p = 0.025), osteoarthropathy (p = 0.0163), hysteromyoma, endometrial polyps (p = 0.049). In the logistic regression model, the only statistically significant indicator of acromegaly was an increase in facial soft tissues (“enlargement of lips”). The inequality ratio for this indicators was 7.34, with a 95% confidence interval (CI) of 1.38–39.11 (p = 0.0196). In the discriminant analysis model, 3 statistically significant indicators were identified that increase the risk of the diagnosis of «acromegaly»: «typical changes in appearance and an increase in the size of the limbs», «enlargement of the lips», «headache». The developed model of discriminant analysis suggested acromegaly in 5 out of 9 patients with a confirmed diagnosis. The area of the ROC curve, which measures the overall ability of the model to discriminate between patients with acromegaly and those without it, was 0.8294. This means that the sensitivity of the model to predicting acromegaly in this study is 55.56%, specificity is 90%  .The data obtained confirm that the real prevalence of acromegaly, especially among the older age group with associated diseases, is significantly higher than that in the analysis of ambulations, which emphasizes the urgency of the problem of timely diagnosis of the pathology . The implementation of the ACROSCREEN program is aimed at identifying a risk group that includes patients with a specific set of clinical, somatic and anamnestic signs and requiring additional diagnostic search. Pursuant to the international experience and our data, the risk group for acromegaly should include patients over 50 years old with impaired carbohydrate metabolism, nodular (diffuse-nodular) goiter, as well as arterial hypertension, cardiopathy, sleep apnea, arthropathy, benign or malignant neoplasias. It should be noted that it is problematic to objectively judge the general epidemiological situation in the Russian Federation on the basis of only one study, therefore, to identify comparable data, similar projects are required in various regions of the country.Based on the results of the work performed, thanks to targeted questioning of patients from the risk group using questionnaires, expert assessment, laboratory and instrumental experimental techniques, the authors were able to identify a fairly high percentage of newly diagnosed patients with acromegaly - 0.72% (9 out of 1249). In similar studies of P.W. Rosario et al. and K. Suda et al. this figure was 0.13 and 0.63%, respectively. High detectability, in our opinion, is due to the selective study of the age group at risk with combined diseases associated with acromegaly, the indispensable inclusion of an endocrinologist in the questionnaire process and an expert assessment of the results obtained. In the future, it is planned to improve the approch of active diagnostic search, especially since this direction is actively developing in world practice. So, in 2016, the results of the population study ACROSCORE were presented, which revealed a strong association of objective signs, indicating the maximum likelihood of acromegaly in the presence of type 2 diabetes mellitus, hyperhidrosis, diffuse (diffuse-nodular) goiter, colorectal polyps, diastema, carpal tunnel syndrome .Given the multiplicity of incoming diagnoses, it is difficult to identically assess the prevalence of acromegaly in the Russian Federation. To calculate the approximate prevalence of acromegaly among patients with associated diseases, the authors identified a cohort of patients with diabetes mellitus. Among this nosology (ICD), the prevalence of acromegaly was 1.9% (5 patients out of 261). Further calculations were carried out according to the scheme proposed by P.W. Rosario et al. . If bearIt should also be considered that in each of these studies, a certain number of patients with «biochemical acromegaly» and an undetected pituitary tumor were found. In the cohort of P.W. Rosario, there were 3 of such patients , in the Late diagnosis of acromegaly, especially with a mild form of the disease , contributes to the development of multiple somatic and metabolic disorders that reduce the quality and duration of life. The use of the ACROSCREEN two-stage selective screening program with preliminary identification of the risk group made it possible to identify 9 (0.72%) patients with acromegaly among patients who had previously received long-term inadequate treatment for another pathology. The real prevalence of acromegaly in the Russian Federation among residents of the older age group with associated diseases significantly exceeds the known rates of ambulations, which requires widespread introduction of targeted diagnostic search technology into the clinical practice.