The mechanism through which GA3 regulates internode elongation has been extensively investigated. In 2019 and 2020, we applied GA3 to the stems, leaves, and roots of two soybean cultivars, Heinong 48  and Henong 60 (a dwarf cultivar), and GA3 was also applied to plants whose apical meristem was removed or to girded plants to compare the internode length and stem GA3 content of soybean plants under different treatments. These results suggested that the application of GA3 to the stems, leaves, and roots of soybean increased the internode length and GA3 content in the stems. Application of GA3 decreased the proportion of the pith in the soybean stems and primary xylem while increasing the proportion of secondary xylem. The apical meristem is an important site of GA3 synthesis in soybean stems and is involved in the regulation of stem elongation. GA3 was shown to be transported acropetally through the xylem and laterally between the xylem and phloem in soybean stems. We conclude that the GA3 level in stems is an important factor affecting internode elongation.Excessive plant height is an important factor that can lead to lodging, which is closely related to soybean yield. Gibberellins are widely used as plant growth regulators in agricultural production. Gibberellic acid (GA According to Bawa et al. [3 and GA7 levels caused by the interaction of low light and high temperature promotes the elongation of soybean hypocotyls. Indeed, changes in the environment lead to an increase in stem GA3 levels and promote stem elongation, which has been confirmed in pea (Pisum sativum L.) [Cardiocrinum giganteum) [Vigna unguiculata (Linn.) Walp.) [3 significantly increases the overall height and length of internodes of plants and reduces internode mechanical strength [3 and GA4 are applied to pea, it was shown that the contents of GA1 and GA8 in the stems decrease, while the GA19 content increases [3 is applied to soybean, the contents of GA1, GA4, and jasmonic acid were shown to have increased, while the abscisic acid and salicylic acid contents decreased [3 reduced the expression of GA2ox1 in soybean. As shown in a study by Bawa et al. [3 promoted GA biosynthesis in soybean, leading to increased GA levels in the plants. Sauter et al. [3 treatment promotes stem elongation by altering the orientation of cellulose microfibrils and that GAs also promote xylem differentiation, regulate cambial cell division, and induce the formation of secondary xylem fibers [3 treatment of Pseudostellaria heterophylla significantly increased the xylem radius and the number of xylem cell layers in the plants, but it had no significant effect on the width of the secondary phloem, cell layers, or vascular cambium [3 treatment of Arabidopsis also resulted in a significantly increased proportion of xylem [Stem elongation stress is an important factor that can result in lodging of plants under shade stress . Gibberem of GAs . When sod leaves ,8. Zhangd leaves  reporteda et al. , the incivum L.) , Himalayganteum) , and cow) Walp.) . Moreovestrength ,16,17,18strength . After Gncreases . In addiecreased . Chen eta et al. , applicar et al.  reportedm fibers ,24,25. G cambium . GA3 treof xylem .3 application is an effective way to alter plant height. Most of the current research reports on the application of GA3 involve the spraying of leaves or soaking of seeds. To investigate the mechanism of soybean internode elongation in response to GA3, we chose Heinong 48  and Henong 60  [3 to these two soybean cultivars, we examined the effects of GA3 on both the soybean internode elongation and the anatomical structure of stem cells and elucidated the pathway through which GA3 was transported in soybean stems via the girding method to provide a basis for understanding the mechanism through which GA3 regulates soybean internode elongation.GAultivar) , two soy3 were the longest, while the results of the V3-GA3 treatment and the control (CK) treatment were not significantly different. In terms of the lengths of the third, fourth, and fifth internodes in response to the different treatments, the patterns were similar; i.e., V1-GA3 > V3-GA3 > CK, and the difference between treatments was significant. The changes in GA3 content in internodes 1–4 were consistent among the treatments, each exhibiting a pattern of V3-GA3 > V1-GA3 > CK, with a significant difference between treatments. At the vegetative 1 (V1) and V3 stages, the application of GA3 to soybean stems increased the internode length and GA3 content. However, the V3-GA3 treatment was not significant effect on the length of the first and second internodes. Taken together, the results showed that exogenous application GA3 to soybean stems could affect the acropetal and basipetal content of GA3 in the stems.As shown in 3 content after GA3 was applied to the leaves resulted in patterns that were similar between the two cultivars . The internode lengths and GA3 content differed significantly among the four treatments. The lengths of the first and second internodes of the plants in GA3+S3307 and GA3 treatments differed non-significantly but were significantly greater than those of the plants in CK and S3307 treatments. Changes in the lengths of the third, fourth and fifth internodes yielded similar patterns: the length of the internodes of plants in the GA3 treatment was significantly greater than that in the other three treatments. The length of the internodes of plants in the GA3+S3307 treatment was greater than that of the plants in the CK and S3307 treatments. Moreover, the length of the internodes of plants in the S3307 treatment was the shortest, and the fifth internode did not grow at all. The stem GA3 content in the plants in the four treatments decreased in the order of GA3 > GA3+S3307 > CK > S3307; the difference between the treatments was significant. On the basis of these results, uniconazole reduced the stem GA3 content and inhibited the promoting effect of GA3 application on internode elongation.3 content after GA3 was applied to soybean plants whose apical meristem had been removed. A comparison of the lengths of different internodes indicated that the three treatments did cause significant differences in the length of the second internode and revealed the same pattern (GA3 > CK > DW) in terms of the length of the third, fourth, and fifth internodes in the two soybean cultivars, with significant differences occurring between treatments. In HN48, the stem GA3 content at the third internode in the GA3 treatment was not significantly different from that in the CK treatment. However, for HN60, the difference was significant. In both cultivars, the stem GA3 content at the third internode in the DW treatment was significantly lower than that in the other two treatments. The stem GA3 content at the fourth and fifth internodes of plants showed the same pattern—GA3 > CK > DW. Thus, the apical meristem of soybean plants plays an important role in controlling internode elongation, and the application of GA3 restores and increases the GA3 level in the stems, promoting internode elongation while substituting for the activity of the apical meristem.3 was applied to different parts of soybean plants after girding. The two cultivars showed the same pattern. The length of the second internode did not differ significantly between the treatments. However, the lengths of the third, fourth, fifth, and sixth internodes of plants in the GG treatment were significantly greater than those in the other three treatments. The lengths of the third, fourth, fifth, or sixth internodes of the plants in the GB treatment were significantly greater than those of the plants in the G or CK treatment, while the length of the internodes of plants in the CK and G treatments did not significantly differ.3 contents in the xylem+ and phloem+ of soybean stems. The GA3 content in the xylem+ at each internode exhibited the same pattern: the GA3 content in the plants in the GG treatment was significantly higher than that in the plants in the other three treatment groups; that in the GB treatment group was significantly higher than that in the G and CK treatments; and that in the CK and G treatments did not significantly differ. On the basis of these results, the girding treatment at the second internode did not affect the xylem+ GA3 content in the soybean plant stems, while the application of GA3 at or below the incision increased the xylem+ GA3 content in the internodes above the second internode, suggesting that the acropetal transport of GA3 in soybean plants occurs mainly through the xylem.3 content in the phloem+ of plants among the four treatments showed a higher phloem+ GA3 content in the upper part of the second internode of the plants in the GG treatment compared with the GB treatment, but the results of the two treatment groups did not differ significantly. Compared with those in the G and CK treatments, the plants in the GG and GB treatments presented significantly higher phloem+ GA3 contents, while the content in the plants in the G treatment and CK treatment did not differ significantly. In terms of the phloem+ GA3 content in the third and fourth internodes of plants, compared with the GB, G, and CK treatments, the GG treatment resulted in significantly higher levels, and compared with the G and CK treatments, the GB treatment resulted in significantly higher levels; however, the contents did not differ significantly between the G treatment and the CK treatment. Taken together, these results showed that the application of GA3 to the xylem and stem cortex increased the GA3 content in the phloem+ of the internodes above the girding site, indicating that GA3 in the stem was transported in both directions through the xylem and phloem. Combining the results shown in 3 content, indicating that the GA3 content in the stem is an important factor affecting stem elongation.A comparison of the GA1, GA3, GA4, and GA7 are the main biologically active forms of GAs and play key roles in plant stem elongation [1 and GA4 levels, and GA1 application to pea seedlings has been shown to promote stem elongation [1 levels. Liu et al. [4 level observed in intercropped soybean plants was the main reason for the elongated stems of those plants. Zhang et al. [3 content. After applying GA3 to soybean plants, Hamayun et al. [1 and GA4 levels in the plants along with a significant increase in plant height. Application of GA3 restored the plant height of transgenic soybean [3 to the stems, leaves, and roots of the two soybean cultivars increased the internode length and stem GA3 level, which is consistent with the results reported by Zhang et al. [3 content. It was also shown that the application of GA3 to stems, leaves, and roots could affect internode elongation. However, it still needs further validation whether exogenous gibberellin can increase the content of GA3 in stems by entering different parts of plants or stimulate the synthesis of more gibberellin in the site of synthesis. In addition, Zhang et al. [3 to Pseudostellaria heterophylla promoted elongation of the stems, while the application of paclobutrazol did not alter the promoting effect of GA3. In the present study, we applied uniconazole (S3307) to the third internode, while GA3 was applied to the second internode of soybean plants in the V2 stage and found that S3307 reduced the stem GA3 content and inhibited the promotion of internode elongation by GA3, which further verifies that the GA3 level in the stem is an important factor affecting soybean internode elongation.GAongation ,30,31. Tongation  and cabbongation  induced ongation . Bensen ongation  revealedu et al.  reportedg et al.  applied n et al.  observed soybean  and rice soybean  with a dg et al. , indicatg et al.  found th3 to cucumber seedlings was shown to significantly increase the elasticity of the walls of stem cells and promote the elongation of hypocotyls [3 to wheat plants at the jointing stage increased the rate of stem elongation but did not affect the height of mature plants [3 to soybean plants in the V1 and V3 stages separately and found that the effect of GA3 application on promoting internode elongation in the V1 stage was significantly stronger than the effect of that in the V3 stage, indicating that the effects of GA3 are affected by the growth state of the internode and that the sensitivity of soybean stems to exogenous gibberellin was different in different growth periods. Notably, the application of GA3 to either the leaf or the root increased the content of GA3 in the stems and promoted elongation of the internodes that were growing. However, for internodes that stopped elongating, GA3 application increased the stem GA3 level but not the length of the internodes.The application of GApocotyls . Moreovee plants . Soybeane plants ; the sec3 promotes the expression of genes related to cell elongation, expansion, and division in tomato [3 application significantly promoted the elongation of the root, stem, and leaf cells of Spondias tuberosa plants [Populus) trees but do not affect the length of epidermal cells or pith cells. In the present study, the application of GA3 also increased the longitudinal length of pith, xylem, and cortex cells in soybean stems; however, the width of these cells did not change significantly, indicating that GA3 increased the length of the internodes by promoting the longitudinal elongation of internode cells, which is inconsistent with the results reported by Eriksson et al. [3 was applied, the xylem radius and the number of xylem cell layers of Pseudostellaria heterophylla plants increased significantly, but the width of the secondary phloem, the number of secondary phloem cell layers, and the width of the vascular cambium did not significantly change [3 to different transgenic Arabidopsis plants significantly increased the proportion of xylem area relative to the total area [3 decreased the proportion of pith in the cross-section of soybean stems and the area of primary xylem while increasing the area of the secondary xylem. How exogenous gibberellin regulated internode elongation through cell changes is not yet clear, which also provides a new direction for future research.GAs are closely related to cell division and expansion . The appn tomato . GA3 appa plants . Erikssoa plants  indicaten et al. . We specy change . The apptal area . In the −1 GA3 in agar; elongation of the stem beyond that of the normal growing plant was achieved after GA3 supplementation [3 content decreased, and internode elongation was inhibited. However, the application of GA3 at the apical meristem removal site restored or even promoted internode elongation while increasing the GA3 content in the stems, indicating that the apical meristem is an important site of GA3 synthesis in the stems of soybean plants and regulates internode elongation.GAs are synthesized mainly in the apical parts of higher plants . In riceentation . In the Arabidopsis and that GAs flowed laterally between the phloem and xylem. However, Mauriat et al. [3 to the stems of soybean plants with girded stems below the incisions and found that the GA3 content increased in both the xylem+ and the phloem+ of the internodes above the girding incision. We inferred that the GA3 absorbed through the cortex is transported to the phloem through the xylem and then acropetally through the xylem. After GA3 was applied at the incision, the increases in the GA3 content in the phloem+ and xylem+ of the internodes above the incision were more profound, indicating that, in soybean plants, GA3 is transported acropetally through the xylem and laterally between the xylem and phloem.GAs may be transported long distances in plants and can act as components of signal transduction ; both int et al.  argued tLodging was the most important factor that affected soybean yield from a practical point of view, and gibberellin was the main reason that caused stem overgrowth. We believe that the data presented in this study, which provides a theoretical basis for regulating the growth of soybean stem, changing plant height, and alleviating lodging under dense planting conditions in the future.2 O5: 46%) and 0.75 g of potassium sulfate (K2 O: 50%). In each pot, three seedlings (spaced 10 cm apart) were retained. The soil was black soil taken from a corn field and presented the following soil fertility parameters in 2019 and 2020: organic matter, 31.9 g kg−1 and 32.7 g kg−1, respectively; available N, 63.0 mg kg−1 and 50.6 mg/kg, respectively; available P, 75.1 mg kg−1 and 53.2 mg kg−1, respectively; and available K, 299.0 mg kg−1 and 247.0 mg kg−1, respectively.A pot experiment was performed from 2019 to 2020 in the experimental field of Northeast Agricultural University, Harbin city, Heilongjiang Province, China . The pots used in this study had an upper diameter of 33.5 cm, a bottom diameter of 24.5 cm, and a depth of 27.5 cm and contained 14 kg of air-dried soil that had been supplemented with 1.50 g of diammonium hydrogen phosphate  for three consecutive days, with normally growing plants serving as CKs. Samples were collected from plants in the V5 stage to measure the internode length and stem GA3 content. Samples were taken from the middle section of the second internode of the V1-GA3-treated plants and CK plants, from which paraffin sections were prepared.GA3 application to soybean leaves: Beginning in the V4 stage, 0.1 g L−1 GA3 solution was applied to the first and second trifoliolate leaves daily, the plants of which were denoted as Leaf-GA3 plants, with the normal plants serving as CKs. When the seventh trifoliolate leaf that emerged from the CK plants, samples were collected to measure the internode length and stem GA3 content.GA3 application to soybean roots: Sand culture was adopted in accordance with the nutrient solution recipe and cultivation method described by Lyu et al. [3 (0.1 g L−1), the plants of which were denoted as Root-GA3 plants, with the normal plants serving as CKs. When the seventh trifoliolate leaf emerged from the CK plants, samples were collected to measure the internode length and stem GA3 content.GAu et al. . Startin3: Starting from the V2 phase, four treatments were established, GA3 (GA3 applied to the second internode), S3307 (uniconazole applied to the second internode), GA3-S3307 (GA3 applied to the second internode and uniconazole applied to the third internode), and CK. Uniconazole was applied until the seventh trifoliolate leaf emerged from the plants in the CK treatment group, after which samples were collected to measure the internode length and stem GA3 content.Inhibitory effects of uniconazole on GA−1 GA3 solution (GA3) or distilled water (DW) was applied daily. Plants from which the apical meristem was not removed were designated the CK group. When the seventh trifoliolate leaf emerged from the CK treatment group, samples were collected to measure the internode length and stem GA3 content.The experiment was conducted in 2019. At the V4 stage, the apical meristem was removed, and the wound was then wrapped with 0.2 g of absorbent cotton, to which a 0.1 g L−1 GA3 solution applied to an area below the incision), GG (0.1 g L−1 GA3 solution applied to the incision area), G (DW applied to the incision area), and a CK (intact plants). Twelve plants per treatment were established, and samples were collected at the V5 stage. The length of each internode was subsequently measured. The internodes were separated into phloem+  and xylem+ (which included the xylem and pith), after which their GA3 contents were determined.The experiment was conducted in 2020. At the V3 stage, the cortex with phloem (width of 5.0 mm) in the middle of the second node of soybean stems was removed by a sterilized blade, and the wound was then wrapped with absorbent cotton to prevent dehydration. Four treatments were established: GB  for 48 h  and then3 content determination: An enzyme-linked immunosorbent assay (ELISA) was used to determine the GA3 content. After the samples were cut, 0.1 g of the freeze-dried sample tissue was accurately weighed, and PBS (pH = 7.4) solution was added for even grinding. The samples were then maintained at 2–8 °C after melting, after which they were centrifuged at 4000 r min−1 for 15 min. The supernatant was then collected and added to an ELISA plate. After adding the enzymes, incubating, washing, coloring, and stopping the reaction, with blank wells serving controls, we determined the absorbance at 450 nm. Stop solution was then added, and within 15 min, the concentration of GA3 was calculated. Each sample was tested eight times.Stem GAp ≤ 0.05 level. The figures were generated using Origin 9.0  and Microsoft Publisher software.Analysis of variance (ANOVA) in SPSS software v.17.0  was used to analyze the different treatments; each treatment was repeated eight times. The means were compared via one-way ANOVA followed by least-significant difference tests at the 3 to the stems, leaves, and roots of soybean plants increased the internode length and stem GA3 content. The application of GA3 decreased the proportion of pith in soybean stems and the primary xylem area but increased the secondary xylem area. The apical meristem is an important site of GA3 synthesis in soybean stems and regulates stem elongation. GA3 was transported acropetally through the xylem and laterally between the xylem and phloem in the soybean stems. We conclude that the GA3 level in stems is an important factor affecting internode elongation.Application of GA


The study of the thermal state of the monolithic adsorbent layer and internal heat exchange processes during the circulating charging of an adsorbed natural gas storage system was carried out. The correlation between the gas flow mode, the dynamic gas flow temperature, and the heat transfer coefficient between the gas and adsorbent was determined. A one-dimensional mathematical model of the circulating low-temperature charging process was developed, the results of which correspond to the experimental measurements.Adsorbed natural gas (ANG) technology is a promising alternative to traditional compressed (CNG) and liquefied (LNG) natural gas systems. Nevertheless, the energy efficiency and storage capacity of an ANG system strongly depends on the thermal management of its inner volume because of significant heat effects occurring during adsorption/desorption processes. In the present work, a prototype of a circulating charging system for an ANG storage tank filled with a monolithic nanoporous carbon adsorbent was studied experimentally under isobaric conditions (0.5–3.5 MPa) at a constant volumetric flow rate (8–18 m Adsorbed natural gas (ANG) storage systems possess a number of significant advantages over compressed (CNG) and liquefied natural gas (LNG) technologies, in particular high energy efficiency caused by the lack of extremely high pressures and cryogenic temperatures as well as increased fire and explosion safety due to the “bound-state” of gas molecules with the surface of the adsorbent, the so-called “nano-dispersed state” . In addiAs a rule, to reduce the influence of thermal effects special thermal management systems can be used: heat exchangers installed inside ,4,5,6,7 −1. Prosniewski et al. [There are also other approaches to deal with the thermal effects of adsorption/desorption processes. For example, in , a passii et al.  consideri et al. .The main correlations for simulating the characteristics of an ANG storage system are presented in ,25.A circulating charging process with thermal management is considered as one of the most promising techniques regarding the implementation of “fast” charging of the ANG system with advanced efficiency. Therefore, this article is dedicated to the experimental study of a full-scale pilot circulating charging system with controlled thermal management for charging an ANG tank prototype filled with monolithic nanoporous carbon adsorbent.Microporous  carbon adsorbents are the most promising materials today for application on ANG due to their high activity to methane, mechanical strength, and the possibility to increase packing density by shaping under pressure ,27,28, wW0 = 0.62 cm3/g, a characteristic adsorption energy of benzene 0E = 19.7 kJ/mol, and an average effective half-width of micropores x0 = 0.61 nm. The manufacturing technology of shaped cylindrical monoliths from AU-1 activated carbon is described in [3. The average diameter and thickness of the monoliths were 196 and 101 mm, respectively. To reduce the hydraulic losses of the samples, 37 perforating channels with a diameter equal to 4.5 mm were made in the monoliths. Monolithic adsorbent samples (14 pcs.) were installed in an adsorption tank of 51 L inner volume. The estimated occupation of the inner space of the tank by the monoliths was about 80%. 2, the edge surface was 0.82 m2, and the surface of the channels was 0.72 m2. Such a number of holes play the role of a flow equalizer rather than increasing the heat transfer surface area.We used the industrial granulated activated carbon AU-1, which possessed a remarkable adsorption activity to methane and could potentially be used in ANG systems . The AU-ribed in . Compare−1. The obtained data on the thermal conductivity of monoliths are in good agreement with the data obtained from a similar active carbon in [The thermal conductivity of the manufactured adsorption monoliths was measured using the MIT-1 material thermal conductivity meter, which is designed to quickly determine the thermal conductivity of various materials by the probe method in accordance with the Russian State Standard GOST 30256-94 . The priarbon in .T0 = 111.67 K, critical temperature Tcr = 190.56 K, and critical pressure pcr = 4.599 MPa.Natural gas used in internal-combustion engines with technical specifications determined by the Russian State Standard GOST 27577-2000  was usedTo study the natural gas charging and discharging processes from the ANG storage system, a special multifunctional experimental setup was developed and manufactured. Photos of this setup are presented in The experimental setup is designed to determine the macroscopic performance indicators for charging of various types, the optimal charging modes, and the time dependencies of various parameters. This setup also allows some indicators of heat and mass transfer to be determined.The main dependencies for calculating the characteristics of ANG storage systems are presented in . CharginA schematic diagram of the experimental setup for study of the thermal management process during circulating charging of the adsorbed natural gas storage system is presented in 3/h. The suction pressure of the compressor is monitored by a PT1 pressure sensor. After compression, the gas is accumulated in the high-pressure tank 2, which consists of two straight-through cylinders with a volume of 65 L each. This tank stores gas at high pressure between experimental studies and supplies gas during experiments. The pressure in this tank is monitored with a PT2 pressure sensor. A medium-pressure tank 3 with a volume of 300 L was designed for storing gas at intermediate pressure, as well as for ensuring safety when working at the experimental setup, since it is the recipient for gas from the entire setup. The pressure in this tank is monitored with a PT3 pressure sensor. The main function of the low-pressure tank 4 with a volume of 430 L is to smooth out pulsations of the gas flow at the suction to the compressor. The pressure in this tank is monitored with a PT1 pressure sensor. Before the experiments, the experimental setup was calibrated with the determination of the volumes of all its elements using an FQI1 gas flow meter and corresponding pressure and temperature sensors.The natural gas used in the experiments was pretreated in the high-pressure gas preparation unit I. The main element of this unit is the natural gas compressor 1, which provides the required pressure up to 25 MPa. The compressor capacity was 14 mIn this scheme, the adsorption heat released during charging of the system is removed using cooled natural gas, which flows through the adsorbent layer of the adsorption tank 5 with a volume of 51 L. This tank has one inlet and two outlets for the gas flow distribution, which makes it possible to reduce the hydraulic losses by up to 8 times with the same adsorber diameter. In fact, the flow was divided nonuniformly, which reduced the effectiveness and feasibility of this solution and made it difficult to analyze the results of the study. Gas circulation is provided by a supercharger 7. During accumulation, new portions of gas enter the circuit from the gas preparation unit I through the pressure regulator PR1 and valve V3. The charging process is carried out in two stages: the organization of isothermal charging with the heat removal into the environment (stage 1) and low-temperature charging with additional heat removal using a cooling unit III (stage 2). During isothermal charging, the heat of adsorption is removed using a “natural gas–air” heat exchanger 6: valves V2, V3, V8, V10, V12, V13, V15 and V16 are open, while valves V1, V4, V5, V6, V7, V9, V11, V14 are closed. During low-temperature charging, the heat of adsorption is removed using a “natural gas–ethanol” heat exchanger 8 to the ethanol cooled by a coolant preparation unit III: valves V2, V3, V9, V10, V12–V14 and V16 are open, while valves V1, V4, V5, V6, V7, V8, V11 and V15 are closed. The ethanol tank 10 is a “cold accumulator” to speed up the low-temperature charging process. The circulation of ethanol is provided by a circulation pump 11.The pressure in the circuit is controlled by a pressure sensor PT4 and is provided by a pressure regulator PR1. The flow rate of the circulated gas is measured by the FT1 flow sensor and is controlled by changing the supercharger rotation speed. Hydraulic losses in the adsorber and heat exchangers are measured using differential pressure sensors PDT1, PDT2, and PDT3, respectively. Temperature measurement at the ends of heat exchangers is carried out using temperature sensors TT4–7.The experimental setup is a closed system. The replacement of natural gas is accompanied by the regeneration of the ANG storage system, which avoids the significant accumulation of gas impurities in the adsorbent.To control the temperature distribution inside the heat-insulated adsorber, temperature sensor tubes were installed in it. The installation diagram of these sensors is shown in A series of thirteen experiments was carried out in a two-stage circulating charging of the ANG storage system. To provide reliable initial data for subsequent research including mathematical modeling, the circulation circuit and heat exchangers were not previously cooled. Their initial temperature and the temperature of the ANG accumulator were close to the ambient temperature, i.e., reliably known. A long period of reaching equilibrium was ensured between the stages.3/h, respectively. In five more experiments at various pressures (from 1.2 to 3.5 MPa), a constant flow mode was maintained in accordance with the Reynolds number in the inlet section of the adsorber . These experiments were carried out with the aim of a more in-depth study of heat and mass transfer processes, excluding errors due to a change in the flow mode during the cooling of natural gas and the adsorber.In eight experiments, the filling pressure and the volumetric flow rate of circulated natural gas were kept constant (with a deviation of less than 3%) and ranged from 0.5 to 3.5 MPa and from 8 to 18 maΔV, i.e., the excess amount of loaded gas in relation to the initial state, was empirically estimated by the “volumetric method” using the gas mass balance in the experimental setup:3 (STP)), where STP is the standard temperature (20 °C) and pressure ; and 3 (STP)), is the gas leaks determined by the rate of decrease in the amount of gas in the experimental setup under the conditions of the closest achievement of the equilibrium of heat and mass transfer in the adsorber, i.e., when the adsorber cooling has slowed down to a minimum level. To evaluate the efficiency of charging in various modes, a number of macroscopic indicators were used, which were determined for the whole adsorber and did not take into account local deviations or differences between the two parts of the adsorber separated by the inlet pipe. The main characteristic of practical importance is the storage capacity of the system. Effective charging capacity The theoretical charging capacity was determined using the current pressure and temperature at a given point in time and data from previous experimental studies of the adsorption properties of AU-1 ,29,37,38eτ, which is counted from the supercharger (circulation) start (differs in experiments) and determined in the experiment by the acceptable final temperature difference ΔeT between the incoming gas flow and the average temperature of the adsorbent. The value of ΔeT determines the direct loss in the storage capacity of circulating charging. A certain effective charging time corresponds to an acceptable loss in storage capacity. For example, the final temperature difference of 5 K corresponds to the theoretical [3 (STP).Charging speed can be estimated using the effective circulating charging time oretical  loss of heK, which is determined by the ratio between the actual heat flux and the maximum heat flux corresponding to an infinitely high heat transfer coefficient or an infinitely large heat exchange surface. The actual heat flux was determined from the theoretical dependences presented in [heK characterizes the balance between the charging mode and the surface area (structure) of the adsorbent monoliths.The efficiency of the heat transfer in the adsorber can be estimated by analogy with heat exchangers using the heat exchange efficiency coefficient ented in ,30 accorSince the two parts of the adsorber, separated by the inlet pipe, differed from each other, the heat exchange efficiency coefficient was determined from the sums of heat fluxes in each part of the adsorber:Evaluation of the heat transfer coefficient in this experiment was not a main target task and, in fact, was a by-product of the study of integral processes of charging a full-size adsorber. The value of the heat transfer coefficient 2∙K)):3); 3); 3); 2/m3).The value of the heat transfer coefficient was estimated by the following equation, , taking into account the space occupied by the adsorbent cRe ≈ 0.48∙fRe . Due to the complex nature of heat transfer, the correct choice of the Reynolds number is difficult: fRe is more reasonable for heat transfer with the edge surface, and cRe corresponds to heat transfer in the channels.The Reynolds number of the flow can be reduced both to the total section of the adsorber Due to the small number of sensors installed in the experimental setup, as well as due to the complex nonuniform gas flow through monoliths, it is impossible to determine the heat transfer coefficients with high accuracy. However, it is possible to determine the general patterns of their change, which can be used in practice, particularly in the development of a mathematical model of the cooled circulating charging process.It was proposed to introduce a simple mathematical model, at the same time correlated with the experiments performed. This mathematical model makes it possible to calculate real charging processes in such systems, though only with the use of monoliths of the same shape and size as in this study. A more general solution is possible in the future when studying monoliths of other shapes and sizes.n cells. The heat transfer area is also considered uniform in the volume of the layer. Heat transfer processes inside the channels and the outer surfaces are not separated from each other. The charging process is isobaric, which greatly simplifies the solution. We neglected the processes of longitudinal  diffusion and thermal conductivity. We also neglected the rate of mass transfer, i.e., we considered the adsorption process to be instantaneous. Also, for simplicity, only the central  adsorbent layer was considered, which made it possible to neglect the heat exchange with the environment, as well as the influence of the metal parts of the adsorber. All parameters of the adsorption layer are uniform inside each cell. The general calculation of the model is reduced to a sequential calculation for each cell. This approach makes it possible, with a small loss of accuracy, to simulate the charging process of a long adsorber by simulating the N number of monoliths, which can be represented as a cell of this model. Since monoliths are often installed with some gaps between them, neglecting the influence of neighboring monoliths fits well with the simplifications of this model. For simpler calculations, the entire adsorber can be considered as a cell, i.e., the adsorber can be calculated by analogy with simple heat exchangers. However, in this study, to improve accuracy, the cell size was an order of magnitude smaller than monoliths.The mathematical model is one-dimensional. The adsorption layer consisting of a number of monoliths is reduced to a layer uniform over charging, divided into 3); and The temperature of the gas leaving the cell This equation is simplified due to neglect of the fraction of the gas flow adsorbed in the cell relative to the circulation flow. In fact, in the entire adsorber, only a few percent or fractions of a percent of the circulating flow are adsorbed, and in individual cells this fraction is negligible.2):Specific heat flux (reduced to the cell section area) in the cell is determined by the temperatures of the entering and leaving gas flows, ; 3); and A change in the temperature of the adsorbent corresponds to a change in the amount of adsorbed gas and the specific enthalpy of the adsorbent, in accordance with the procedure described in ,30. DespIn this work, the method of successive approximations was used to improve the accuracy of the solution; however, when choosing small steps The heat transfer coefficient 3 (STP) with isothermal charging and 6.71–7.16 m3 (STP) with low-temperature charging. The differences are probably due to the existing measurement errors , unaccounted for unstable leaks, and the nonuniform accumulation of impurities from natural gas. In specific terms, the effective capacity was 96–100 m3 (STP)/m3 for isothermal charging and 132–140 m3 (STP)/m3 for low-temperature charging. This value does not include the initial amount of gas (about 20 m3 (STP)/m3), part of which can be extracted during desorption with heating the adsorbent. In addition, the adsorbent filled approximately 80% of the internal volume of the adsorber, so that when the charging technique is refined, a specific effective storage capacity of 175 m3 (STP)/m3 can be reached in the limit. The results in The highest achieved effective storage capacity in the experiment was 4.88–5.12 mheK in all the experiments was rather high (from 0.62 to 0.83), which indicates an acceptable surface area of monoliths for these charging modes. This is a somewhat unexpected result, since it was assumed that the small number of channels in the monoliths might not be enough for efficient heat transfer. Experiment 5 had the highest heat exchange efficiency coefficient. This is likely due to the combination of both high pressure, which provides intense heat exchange, and low gas flow rate, which ensures sufficient gas heating.The value of υ of the low-temperature charging for the main group of experiments (from 1 to 8), while the achieved effective charging capacity in the experiment is taken as 100%. In relative coordinates, excluding leakage and the accumulation of impurities, the correspondence between the theoretical amount of gas and the experimental storage capacity is more obvious. The stepped shape of the curves is due to the supply of gas in portions. This figure clearly shows the difference in the duration of low-temperature charging in different modes. Charging 80% of the maximum can take from 4 min at 3.5 MPa, in experiments in which low-temperature charging gives a small increase in the amount of gas, up to 52 min at 0.5 MPa, and 90%, respectively, from 13 min at 3.5 MPa to 80 min at 0.5 MPa. At a pressure of 1.0 MPa (experiments 6 and 7), a good balance can be observed between the duration of the low-temperature charging and the increase in the amount of gas (up to 1.9 times). This pressure is interesting for practical application in the case of direct gas supply from the gas distribution network or with preliminary compression in a one- or two-stage compressor.3/h (Experiment 1). There is a clear heterogeneity in the cooling of one half of the adsorber compared to the other: the adsorbent in the area of sensors 1 and 6 is cooled much faster than in the area of sensors 8 and 9. Ensuring the uniformity of gas flow distribution seems to be one of the most difficult technical problems in real systems: dust of the adsorbent, clogging filters, and so on can significantly distort the distribution of flows. It was found that the approximate ratio of gas flow rates was 2.5:1, and it completely changed the nature of the adsorber cooling and, probably, increased the duration of charging.The study of heat exchange processes at the micro level was not initially included in the experiment. This is noticeable by the small number of temperature sensors installed in the adsorber and a number of simplifications used, such as a linear axial temperature gradient. This resulted in rather large errors in the experimental heat transfer coefficients. However, the experiment made it possible to evaluate a number of patterns in the change in the heat transfer coefficients, which in turn made it possible to implement a simple one-dimensional mathematical model of the adsorber charging. The process of heat transfer in the adsorbent layer in this case is rather complicated, since the final result is influenced by heat transfer on the surface of the cylindrical channels; heat transfer along the end surfaces of monoliths; thermal conductivity of the adsorbent layer; mass transfer providing gas movement through the adsorbent layer; heat release in the adsorbent itself, taking into account possible accumulations of impurities; heat leakages from the environment; heat capacity of the adsorber tank itself, especially from the flange side, and so on. The nonuniform distribution of the gas flow with its possible slip through the radial gaps between the monoliths and the adsorber walls has a negative impact on the accuracy of prediction and the determination of experimental heat transfer coefficients. Also, there are temperature measurement errors, including inertia of the temperature sensors, and simplifications in the experimental and data processing methodology, such as a linear axial temperature gradient. Considering all of the above, further results should be considered approximate and estimated, although they can be used in practice with appropriate safety factors when calculating the adsorber and the charging process with a similar working substance and a similar adsorbent (with the same adsorption properties and monolith geometry).Analysis of the approximate experimental heat transfer coefficients 2∙K)):−1):Analysis of the estimated experimental heat transfer coefficients The limits of applicability of Equation (9) are determined by the conditions achieved in the experiment. If Equation (9) is given a physical meaning, then Equation (9) can only be used in the case of a similar adsorbent and working substance. The advantage of Equation (9) is its simplicity. It is also worth noting the value of the degree at the Reynolds number of 0.78, which is very close to the typical degree of 0.8 in heat transfer processes in turbulent flow. However, this also reveals the drawback of Equation (9), which is that it does not consider different types of flow, since most of the experiments fell into the region of turbulent and transient flows, and very little into the region of possible laminar flow in channels .3/h) or a constant flow mode . The results of the study showed the correlation between the charging mode and the charging efficiency indicators. The fastest low-temperature charging was achieved at a pressure of 3.5 MPa and a gas flow rate of 12 m3/h. The highest achieved specific effective  storage capacity in the experiment was 100 m3 (STP)/m3 for isothermal charging and 140 m3 (STP)/m3 for low-temperature charging, and up to 175 m3 (STP)/m3, when reduced to the volume of the adsorbent. At a pressure of 0.5 MPa, the low-temperature charging provided a significant increase in the effective capacity of gas by 116%, but it took a very long time (80 min to reach 90% of the maximum storage capacity). The most balanced heat exchange process was observed in the charging mode at a pressure of 2.0 MPa and a gas flow rate of 8 m3/h: the efficiency of using the refrigerating potential of the gas flow reached 83%. In general, the heat exchange was quite efficient for the used charging modes, which indicates a sufficient heat exchange area of the monoliths. The correlation between the heat transfer coefficient and the gas flow mode for circulating charging was determined. A one-dimensional mathematical model of the adsorber charging process was developed using the experimentally estimated heat transfer coefficients between the adsorbent and the gas. The simulation results of the dynamic temperature of the sensors inside the adsorber are in adequate accordance with the experimental results (error less than 3.6 K with a confidence level of 95%).Studies of the process of circulating natural gas charging were carried out on a full-scale adsorber with a volume of 51 L equipped monolithic adsorbent in two modes: isothermal and low-temperature charging. The studies were carried out by providing a constant pressure (from 0.5 to 3.5 MPa) and a constant volumetric gas flow rate (from 8 to 18 m


Ultrasound-Guided Triamcinolone Acetonide Hydrodissection for Carpal Tunnel Syndrome: A Randomized Controlled Trial” by Wang et al. , 1 mL of 2% lidocaine, and 8 mL normal saline or ultrasound-guided perineural injection with 1 mL of triamcinolone acetonide (40 mg/mL) and 1 mL of 2% lidocaine.” That is, the first group received 1 mL of 10 mg/mL triamcinolone acetonide and the second group received 1 mL of 40 mg/mL drug. However, the “Methods” section of the text stated, “The injection .” Could the authors kindly confirm the steroid dosage in each group? We believe this could be a very significant confounding variable.Even with the same concentration of 10 mg/mL triamcinolone added as the injectate of the two patients groups, the final concentration of the triamcinolone reaching the nerve or remaining in the carpal tunnel may be significantly different. First, the final concentration of triamcinolone in group 1 was 1 mg/mL (10 mg per 10 mL of solution), and for group 2, it was 5 mg/mL (10 mg per 2 mL of solution). Second, the corticosteroids effects on CTS are believed to be due to the anti-inflammation to lessen the intracarpal pressure for symptoms relief; therefore, ultrasound guidance is crucial . AssuminWe share a This commentary significantly points out the critical endpoint of the ultrasound-guided hydrodissection of the MN used in CTS. All the tethering fibrotic or scar tissues over both above and below the MN, over both the ulnar and radial sides of the MN, should be hydrodissected, and the final hydrodissected MN should appear rounded/oval for the best results and prevention of recurrence. This letter also further draws attention to the possible contribution of ultrasound-guided hydrodissection of nerves on the treatment of entrapment neuropathy as in CTS.All authors have contributed significantly in the idea formation, writing, literature collection, editing, reviewing, and final agreement of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Background: The purpose of this study was to provide a comprehensive assessment of the impact of the COVID-19 pandemic on the epidemiology of primary and revision arthroplasties of the hip and knee joint. Methods: This study compared the data on knee and hip arthroplasty procedures from 2 hospitals (primary and revision) conducted in two periods: the period of the COVID-19 pandemic in Poland (from 4 March 2020 to 15 October 2020) and the corresponding period prior to the pandemic (from 4 March 2019 to 15 October 2019). We compared the epidemiological data, demographic data, and hospital stay duration data from these two periods. Results: Our analysis demonstrated that the total number of hip arthroplasties conducted in 2020 decreased by 26% in comparison with 2019. In the case of knee arthroplasties, the total number of procedures in the evaluated period in 2020 decreased by 44%. Our study also showed that the mean time of hospital stay for orthopedic patients following hip or knee arthroplasty was 22.87% shorter. The female-to-male patient ratio decreased between the analyzed periods, and this was 22.96% lower during the pandemic. Conclusion: The COVID-19 pandemic in these two hospitals in Poland led to reduced numbers of hip and knee replacement procedures, shorter hospital stays, and a decreased female-to-male patient ratio. The mean age of patients undergoing hip or knee arthroplasty remained unchanged during the national lockdown with respect to the pre-pandemic figure. The most common indication for primary total hip or knee replacement is advanced osteoarthritis, with associated pain, problems with daily functioning, lower quality of life, and limited range of motion . The indThe COVID-19 pandemic resulted in global changes in the functioning of healthcare facilities in 2020 ,17,18,19The important issue of the effect of the COVID-19 pandemic on the epidemiology of primary and revision hip and knee arthroplasties has been neither fully investigated nor understood. The available literature reports have estimated the effect of the COVID-19 pandemic on reduction in the number of hip and knee replacement surgeries in the United States, European centers where elective arthroplasties and revision arthroplasties are performed, and hip and knee arthroplasties conducted in Italy ,3,4,5,10The epidemiology of hip and knee arthroplasties appears to have changed during the COVID- 19 pandemic. Most of the differences in the time of stay in hospital for patients and the total number of operations are not due to the COVID- 19 pandemic, but because of the health procedures followed, and sometimes because of patients’ fear of long stays in health facilities and the chances of them being infected with COVID19.The purpose of this study was to provide a comprehensive assessment of the impact of the COVID-19 pandemic on the epidemiology of primary and revision arthroplasties of the hip and knee joint in 2 hospitals in Poland.This study analyzed the epidemiology of primary and revision hip and knee arthroplasty procedures conducted at two orthopedic centers in Poland dealing with this type of procedure, as well as medical rehabilitation. The medical database of all data for all patients at our hospital was analyzed to collect data for this study. Our analysis included a comparison of data collected during the period of the COVID-19 pandemic in Poland (between 4 March 2020 and 15 October 2020) with those collected during the corresponding pre-pandemic period (between 4 March 2019 and 15 October 2019). The study was approved by the local review board.The inclusion criterion was a history of one of the following procedures, i.e., total hip arthroplasty, total knee arthroplasty, revision arthroplasty of the hip, or revision arthroplasty of the knee, during one of the evaluated periods . The collected data was analyzed for the total number of hip and knee arthroplasties; total number of women who underwent a hip replacement surgery (primary or revision); total number of men who underwent a hip replacement surgery (primary or revision); total number of women who underwent a knee replacement surgery (primary or revision); and total number of men who underwent a knee replacement surgery (primary or revision). In addition, we analyzed the mean age of patients  who underwent a knee replacement surgery (primary or revision); mean age of patients  who underwent a hip replacement surgery (primary or revision); mean age of these orthopedic patients, irrespective of their sex, who underwent a hip replacement surgery (primary or revision); and mean age of patients, irrespective of their sex, who underwent a knee replacement surgery (primary or revision). Moreover, we evaluated the mean duration of hospital stay following (primary or revision) hip replacement surgery ; mean duration of hospital stay following (primary or revision) knee replacement surgery ; and the ratio of female to male patients.All the evaluated data from the period of the COVID-19 pandemic in Poland (from 4 March 2020 to 15 October 2020) were compared with the corresponding data from the period prior to the COVID-19 pandemic in Poland (from 4 March 2019 to 15 October 2019).The obtained data were statistically analyzed using the Statistica 13.1 software. Pearson’s chi-square test, t-student test, Mann-Whitney U test, correlation analysis and one-way ANOVA were used to compare the variables. Pearson’s chi-square test was used to assess the relationship between the frequency distribution of responses in one variable with respect to the other variable. Student’s t-test was used to compare the continuous variables for two groups (during and before the pandemic). The level of significance was set at α = 0.05.All results are presented in p = 0.0456).Our analysis demonstrated that the total number of hip arthroplasties conducted in 2020  decreased by 26% in comparison with the number of hip arthroplasties conducted in the corresponding period in 2019. This difference was statistically significant , (p = 0.p = 0.0024).In the case of knee arthroplasties, the total number of procedures in the evaluated period in 2020 decreased by 43.86% in comparison with the number of knee arthroplasties conducted in the corresponding period in 2019. This difference was statistically significant , (p = 0.p = 0.24723).The total number of hip revision conducted in 2020 decreased by 30%. The total number of knee revision conducted in 2020 increased by 100%, but this difference was not statistically significant (p = 0.012). The mean time of hospital stay for patients following hip revision was 34.05% longer (from 9.25 days to 12.4 days). However, this difference was not statistically significant (p = 0.53931). The mean time of hospital stay for patients following knee revision was 43.75 % shorter (from 8 days to 4.5 days). This difference was not statistically significant (p = 0.35007).Our study also showed that the mean time of hospital stay for orthopedic patients following hip or knee arthroplasty was 22.87% shorter (from 7.52 days to 5.8 days). This difference was statistically significant , (p = 0.p = 0.1557). The mean age of patients following hip revision during the pandemic increased (from 74.75 years in 2019 to 77 years in 2020), but this difference was not significant. The mean age of patients following knee revision during the pandemic increased (from 62 years in 2019 to 70.25 years in 2020). However, this difference was not significant.The mean age of orthopedic patients undergoing the evaluated procedures during the pandemic was lower (from 70.19 years in 2019 to 68.13 years in 2020). However, this difference was not significant (p = 0.02813).The female to male patient ratio decreased between the analyzed periods, and was 22.96% lower during the pandemic. This difference was statistically significant , (p = 0.Due to the large number of patients with hip and knee arthropathy worldwide and, consequently, the total number of hip and knee replacement operations globally ,2, it isPrevious studies assessed the effects of the COVID-19 pandemic on lowering the numbers of hip and knee arthroplasties conducted in the United States, European centers conducting primary and revision elective arthroplasties, and hip and knee arthroplasties conducted in Italy ,3,4,5,10The COVID-19 pandemic has considerably altered the way the entire healthcare systems operate, including the way orthopedic wards function ,17,18,19Bedard estimated a 75–100% drop in the number of hip and knee arthroplasties during the pandemic in the United States . There wThere have been no studies evaluating the impact of the COVID-19 pandemic on the age of patients undergoing hip or knee replacement surgeries. Our study showed no significant effect of the national lockdown in the mean age of patients who underwent hip or knee primary and revision arthroplasty. The observed lack of a decrease in the mean patient age seems to be associated with patients in our orthopedic ward being highly determined to undergo their elective orthopedic procedures.There have been no studies assessing the effect of lockdown measures on the mean duration of hospitalization for hip or knee replacement surgery. The data from our center showed the mean duration of hospital stay after primary and revision knee surgery during the pandemic to be shorter than that prior to the pandemic. This was due to several factors: doctors were more eager to expeditiously discharge orthopedic patients from the ward to minimize the risk of COVID-19 infection; in-hospital rehabilitation facilities were more accessible than at other times, which accelerated the patients’ postoperative recovery; and the patients themselves were more eager to be discharged for fear of COVID-19 infection.There has been a scarcity of data on the effect of the COVID-19 pandemic on the ratio of females to males among those patients who undergo hip or knee replacement. Some authors report higher numbers of hip and knee replacements being conducted in women than in men [One limitation of our study is the fact that the analyzed epidemiological data came from two centers. In the future, we are planning a multi-center study to broaden the scope of evaluated data. In this light, due to the fluid nature of the COVID-19 pandemic, findings reported may not be relevant for all countries going forward.Our study showed a significant impact of the COVID-19 pandemic on the epidemiology of hip and knee arthroplasties.The COVID-19 pandemic in our two orthopedic wards in Poland led to reduced numbers of hip and knee primary replacement procedures, reduced numbers of hip revision, increased number of knee revision, shorter hospital stays, and decreased female-to-male patient ratio.The mean age of patients undergoing hip or knee arthroplasty remained unchanged during the national lockdown with respect to the pre-pandemic figure.The COVID-19 pandemic in our two orthopedic wards in Poland has not led to the number of hip and knee arthroplasties conducted to drop as dramatically as it has in other European centers and centers the United States.


The cyclic alternating pattern is the periodic electroencephalogram activity occurring during non-rapid eye movement sleep. It is a marker of sleep instability and is correlated with several sleep-related pathologies. Considering the connection between the human heart and brain, our study explores the feasibility of using cardiopulmonary features to automatically detect the cyclic alternating pattern of sleep and hence diagnose sleep-related pathologies. By statistically analyzing and comparing the cardiopulmonary characteristics of a healthy group and groups with sleep-related diseases, an automatic recognition scheme of the cyclic alternating pattern is proposed based on the cardiopulmonary resonance indices. Using the Hidden Markov and Random Forest, the scheme combines the variation and stability of measurements of the coupling state of the cardiopulmonary system during sleep. In this research, the F1 score of the sleep-wake classification reaches 92.0%. In terms of the cyclic alternating pattern, the average recognition rate of A-phase reaches 84.7% on the CAP Sleep Database of 108 cases of people. The F1 score of disease diagnosis is 87.8% for insomnia and 90.0% for narcolepsy. Sleep, which accounts for nearly a third of human life, is an important function that helps the body to recover. It has been proven that sleep could help to reduce stress, regulate hormone balance, stabilize appetite and cardiovascular function ,2,3. At Sleep is known to rhythmically regulate autonomic nervous system activity. Quiet sleep is associated with increased parasympathetic arousal and activity, while rapid eye movement (REM) sleep is relevant to the increased sympathetic activity . The sleMany researchers suggest that both slow and fast electroencephalogram (EEG) activation complexes are involved in the structural organization of sleep . Deep slThe Cyclic Alternating Pattern (CAP) is the periodic EEG activity occurring during NREM sleep. It is characterized by cyclic sequences of cerebral activation (phase A) followed by periods of deactivation (phase B) which separate two successive phase A periods with an interval <1 min . Phase APhase A periods are subdivided into three subtypes. The abundance of A1 subtype in the descending branches and grooves may be an EEG expression of brain mechanisms involved in release activity, while the dominance of A2 and A3 subtypes in the ascending branches reflects the REM-on drive . TherefoSeveral efforts have been made to develop a reliable automatic CAP-scoring algorithm ,21,22,23Some researchers and institutions have tried to classify sleep stages by physiological signals instead of EEG. As physiological signals that contain the physiological characteristics and autonomic nerve status information of the human body, Electrocardiograph (ECG), respiration and the three-axis acceleration signals on the chest have attracted much attention ,32,33. WConsidering the connection between the heart and brain of people ,40,41, tIn this research, we first expanded the index system of CRI, combined with the physiological significance of the cardiopulmonary coupling model. CRI in different sleep stages of different people were analyzed in detail in this paper. Inspired by the results of the statistical analysis of the cardiopulmonary characteristics of healthy people and patients with sleep-related diseases, we proposed an automatic recognition and disease diagnostic scheme of CAP based on CRI. The scheme combines the variation and stability of CRI using Hidden Markov  and RandIn this paper, for materials and methods, This section describes the data set and the data processing in this research.The experimental data used in this study is obtained from the CAP Sleep Database  in MIT-BThe database includes 108 cases of people with non-pathology and several sleep-related pathologies. Expert neurologists who trained at the Sleep Center provided the scoring of the sleep macrostructure, according to the Rechtschaffen & Kales rules , includiThe The ECG and respiration signals of people with non-pathology, insomnia and narcolepsy are used in this study. For the signals in the database, stationary signals are selected for analysis. res represents the respiratory signal, psd represents power spectral density function. Q value expresses the concentration degree of the power spectrum of respiratory signal, and the stability of respiratory frequency. Considering the respiratory signal is concentrated in the frequency domain from 0.03 Hz to 0.5 Hz [Q > 0.85 are chosen [Wavelet analysis is used to remove the baseline drift of the signal and a Pasteur band-pass filter is used to remove the noise. Then, for respiratory signals, we define the signal quality function as follows:o 0.5 Hz , the sige chosen ,52. ThisRRI is the RR intervals, RRIi−1 and RRIi are adjacent intervals.As for the ECG, to ensure RR intervals  in the normal range and without a mutation because of premature beat or other physiological phenomena , we use After processing ECG and respiratory signals, we calculated CRI sequences taking the step size of 10 s with the window of 120 s.G-causality [Cardiopulmonary interaction is important in the circulation system to ensure efficient delivery of oxygen and nutrients, and that the efficiency is optimized at the state of cardiopulmonary resonance. Cardiopulmonary resonance indices (CRI) come from the bivariate autoregressive model of respiration series and RR intervals. The model could calculate respiratory along with the non-respiratory component effects on RR intervals in the frequency domain based on ausality .RRI was regarded as a Markov process, ignoring other factors affecting heart rate in the short term, the RRI and RSP (both of length T) were described by a bivariate auto-regressive model [p is the maximum number of lagged observations included in the model . A contains the coefficients of the model, and ε1, ε2 are the residuals for each time series.In the model, the change process of ve model :(3)RRI and unrestricted (U) models:R(12)1 is derived from the model omitting the Aj12,  coefficients in the first equation and εU1 is derived from the full model [G(f) which measures the cardiopulmonary interaction in the frequency domain.By the definition of ll model . In ordeG(f) in the frequency domain, CRI are defined to measure the status of the cardiopulmonary resonance system by adopting the cardiopulmonary system circuit model [Based on it model ,55,56  in the frequency domain [CRI include cardiopulmonary resonance amplitude (CRA), cardiopulmonary resonance bandwidth (CRB) and cardiopulmonary resonance quality factor (CRQ) shown in y domain . Reflecty domain  and in ty domain .CRQ is defined to measure the merit of the cardiopulmonary resonance system by adopting the quality factor measure for inductor, capacitor, and resistor LCR oscillator. Combined with the physiological significance of the cardiopulmonary coupling model, we expanded the index system with non-respiration factors, which is an analogy with the energy consumption element in the circuit model, as cardiopulmonary resonance resistance (CRR).AF represents the cardiopulmonary resonance frequency. Then we define the cardiopulmonary resonance resistance (CRR) as follows [In the oscillating system, the quality factor of a circuit is the ratio between the reactance power and the average power consumed by the resistor, namely the ratio of reactive power and active power. In the non-radiative system, the capacitive reactance is equal to the inductive reactance at resonance, then we can deduce :(5)CRQ=1 follows :(6)CRR=2Cardiopulmonary resonance resistance (CRR) represents the physiological phenomena of people that exist in the heart rate variability excluding the respiratory modulation, and is related to pathological state of the subject.CRA, CRB, CRQ and CRR jointly constructed the evaluation index system of cardiopulmonary coupling. In the following analysis, we constructed the sleep analysis scheme by using the performance of the four indicators  in different groups. The significant difference of the CRI in A-phase and non-A phase (NA-phase) period were detected by the repeated one-way ANOVA test.Inspired by the results of the statistical analysis of the cardiopulmonary characteristics of healthy people and patients with sleep-related diseases, we propose an automatic recognition and disease diagnostic scheme of CAP based on CRI. Using the Hidden Markov and Random Forest model, the scheme combines the values and stability of characteristics which measure the status of cardiopulmonary system of people during sleep. Precision and recall rates will be calculated in the next section.The flow of the classification and diagnosis scheme is shown in the The classification algorithm in this paper uses a total of 21 features, consisting of three body movement (BM) features, 12 heart rate variability (HRV) features and six CRI features. Each kind of data is preprocessed.Body movement (BM) features  include During the training process, to improve the effectiveness of the extracted features, for the sleep stage WEAK, LIGHT SLEEP (stages S1 and S2) and DEEP SLEEP (stages S3 and S4), 20 consecutive tagged data is selected as the training data, that is, the data remaining unchanged in sleep status within 10 min is selected as the initial training data. For the identification of A1-phase, A2-phase and A3-phase, all the data are used. When the value of the calculated feature exceeds the normal range, the data fragment is preprocessed again, and the outliers are compensated until the eigenvalue is normal. The scheme adopts the combination of Hidden Markov and Random Forest model to fully utilize the variation and stability of features.The Hidden Markov Model is used to characterize both the stability and the variation of CRA between different sleep stages, and the final recognition scheme is realized by the Random Forest Model. The Hidden Markov Model is a probabilistic model of timing sequences. It can learn the implicit characteristics of states by observing phenomena. The transformation process between sleep stage is a Markov process with implicit temporal information. The physiological signals and sleep states can be observed, while the numerical characteristics of physiological significance of the state transitions are unclear. Therefore, we choose the hidden Markov model as the initial model. In this study, for each subject, the transformation between the sleep stages and phases is a Markov chain. I is the state sequence of 18 dimension, and O is the corresponding observation sequence of CRA.We take the CRA sequence as the observation sequence and the label of the sleep stages as the state sequence. There are 18 kinds of sleep stages in this study, including WEAK, S1 , S2 , S3 , S4  and REM. A is the probability matrix of the observation transition:ija is the probability of the transformation to jq at time t + 1, given iq at time t.In the CAP classification scheme, firstly, we train the HMM  for CRA The Random Forest Model has natural advantages for classification tasks with many features and incomplete sample size, with high accuracy and fast training speed. It is suitable as our final classifier. The training and classification work are carried out in two layers, the first layer is carried out for identification stage WEAK, stages REM, S1, S2, S3 and stage S4, while the second layer is carried out for identifying A1-phase, A2-phase and A3-phase in S1/S2/S3/S4, respectively. The clarification of the two layers both used Random Forest Model. SVM  is used This section describes the statistical analysis of the cardiopulmonary characteristics of people with non-pathology and several sleep-related pathologies.The deep sleep stage period (including stages S3 and S4) during the whole sleep, in which the human body is least affected by external noise and voluntary activities, shows more remarkable physiological significance in analyzing statistical results . PreviouTherefore, CRI characteristics  in people with non-pathology, insomnia and narcolepsy during the DEEP SLEEP period were analyzed. The results are shown in the In the bar chart For the analysis of CAP mode, the repeated one-way ANOVA, followed by Dunnett’s post hoc test  is used p < 0.05, there is significant difference between the groups. We calculated the p value of CRA in S3 and S4: p = 0.004. For Dunnett’s post hoc test, if the value of difference of the mean > LSR, there is a significant difference between the groups being compared. It is a method of comparing means in analysis of variance to judge whether the influence of CRA on the sleep stage is significant . For repIn the In the groups with non-pathology, insomnia and narcolepsy, by comparing the performance of CRA in period A1-phase, A2-phase and A3-phase in sleep stages S1, S2, S3 and S4 shown in In the non-pathology group, in stage S4, there is a significant drop in CRA from A2 to A3; in stage S3, there is a huge drop between A1 and A2, whereas S1 and S2 are inherently less coupled. CRA of A3 in stages S3 and S4 is lower than in stages S1 and S2 in the NA-phase. In insomniacs, CRA of A3-phase in stage S3 is very low, while it is very high in the NA-stage. We can see that CRA fluctuates greatly between phase A and non-Phase A. This may be a compensatory mechanism of the autonomic nervous system in insomniacs. In narcolepsy, the CRA in S3 and S4 is small regardless of whether they are in an A-phase or NA-phase period.To facilitate the analysis and comparison between three groups, Overall, from the detailed analysis of the cardiopulmonary characteristics of different groups during the sleep period, we could see that CRI characteristics  in people with non-pathology, insomnia and narcolepsy are different during the whole sleep. The CRI could help diagnose insomnia and narcolepsy. In the CAP mode of different groups, both the variation and stability of CRA characteristics are significantly different. Constructing a classifier combining variation and stability can help us to recognize CAP more accurately.To illustrate the classification performance and generalization ability of the scheme, we conducted the 7-fold cross-validation . We provThe sleep stage classification results are shown in the confusion matrix In order to express classification accuracy and generalization performance form i stands for class i, including WEAK, REM and A1, A2, A3 and NA from stage 1 to stage 4. The precision refers to the specific gravity of the positive sample in the positive example determined by the classifier; recall refers to the proportion of the total positive cases that are predicted to be positive. Then the final F1 score in CAP experiments is [In this formula, ments is :(11)F1=∑According to the In detail, about the identification of A-phase, the accuracy in stages S1, S2, S3 and S4 are 84.4%, 90.1%, 84.2% and 79.9% respectively. The average recognition rate of A-phase reaches 84.7%. Similarly, in terms of disease diagnosis, the F1 score of diagnosis and recognition is 87.8% for insomnia and 90.0% for narcolepsy. For real cases, this table could help to analysis differences between the results of sleep classification and the actual sleep structure easily.CRI characteristics  in people with non-pathology, insomnia and narcolepsy are different in all stages during the whole sleep. Compared to people with non-pathology, insomniacs show higher CRQ and lower CRR, while narcolepsy patients have the opposite manifestations. The CRB of the healthy group is significantly higher than the CRB of insomniacs and narcolepsy. At the same time, the CRA of insomniac patients is higher than the healthy group, while the CRA of narcolepsy patients is significantly lower than that of the healthy group. This phenomenon can be considered as a compensation of autonomic nerve of insomniac patients. Meanwhile, the coupling depth CRA and coupling width CRB of narcolepsy patients are always low during the whole sleep. In the CAP, in stage S4, there is a significant drop in CRA from A2 to A3; in stage S3, there is a sharp drop between A1 and A2, whereas S1 and S2 are inherently less coupled. CRA of A3 in stages S3 and S4 is lower than in stages S1 and S2 in the NA-phase. These performances support the conclusions including the presence of heart-brain connection  and the In the CAP mode of different groups, both the variation and stability of CRA are significantly different. Our scheme using improved HMM and RF combines these two points well. The average recognition rate of A-phase reaches 84.7% and the F1 score in the CAP experiments reaches 80.4%. In order to illustrate the role of CRI features in the scheme, as the control group, the features related to CRI were removed while the remaining features were used. After the training of the Random Forest Model and 7-fold cross-validation test, the F1 score of CAP classification is 73.8%. The F1 score of disease diagnosis is 71.6%. Besides, as comparison, features in references ,36,37,38It can be seen that the performance of the CRI surpasses that of the features in other studies in sleep stage classification, especially in CAP pattern recognition. In the diagnosis of sleep-related disorders, CRI significantly outperforms other features.The performances of ‘removing CRI’ and ‘CRI’ are better than the other benchmark papers, such as ,36,37,38CRI characteristics quantify the coupling status in the cardiopulmonary system, and could express the activity characteristics of autonomic nerve regulation. These autonomic nerve regulation characteristics are determined by EEG, and ultimately manifest as tiny periodic changes in sleep stages. At the same time, using Hidden Markov and Random Forest model, the scheme proposed combines the values and stability of these characteristics during sleep. This makes the results of classification more accurate. For the groups with non-pathology, insomnia and narcolepsy, CRI show significant differences in various stages of sleep and express the pathological features of the disease. Thus CRI make the framework more effective in diagnosing diseases. The results of the scheme, on the one hand, prove the existence of a heart-brain connection, and on the other hand, verify the validity of CRI in the expression of the cardiopulmonary coupling and autonomic nervous activity of human being. The scheme is also helpful to identify insomniac patients and narcolepsy patients. Cyclic Alternating Pattern (CAP) is a sensitive tool for studying sleep disorders throughout the life cycle. Several efforts have been made to develop a reliable automatic CAP-scoring algorithm. Most of these methods rely on the extraction of spectral features from the EEG.Considering the connection between the heart and brain of people, we analyze the cardiopulmonary characteristics of cardiopulmonary resonance indices (CRI) in people with non-pathology, insomnia and narcolepsy under the CAP mode. We analyze and identify key fields that contribute to insomnia and narcolepsy. The results show that CRI have different manifestations in different groups. The conclusion is drawn that CRI are capable of representing the cardiopulmonary coupling degree, autonomic nerve state and sensitivity of the subjects, and thus are able to measure the health status of human body.Inspired by the results of the statistical analysis of the cardiopulmonary characteristics, our CAP Recognition and Disease Diagnostic scheme uses CRI in the frequency domain as the feature to recognize the A-phase stage during the whole sleep.There are many trials in pattern recognition using Hidden Markov and Random Forest model. Different methods have shown superiority in different applications. The scheme in this article takes both variation and stability of measurements of coupling state of the cardiopulmonary system during sleep into account. The precision and recall show the good performance of the scheme.The proposed method is effective to conquer the weakness about the signal acquisition and processing in clinical trials, particularly when we consider the stress of the examinee and the cost of measurements using the conventional Rechtschaffen & Kales rules . ResultsTo develop a classification and diagnosis scheme for a specific hospital, the clinical data and expert opinions should be added into the scheme. It could be interesting to see how these contribute to the prediction accuracy.Furthermore, the meaning and application of CRI are also worth exploring, such as the psychological stress, inflammation, etc.


Background: The number of cancer patients is constantly growing. Both WHO and IARC report that this number may reach up to 24 million new diagnosed cases in the next two decades. The proposed treatment and especially the diagnosis can have a significant impact on an individual's approach to the disease, as well as on the patient's quality of life.Objectives: The study aimed to assess the quality of life, feelings, and fear of cancer-treating oncological patients, before and during the COVID-19 pandemic.Material and Methods: The study used the standardized WHOQOL quality of life questionnaire in a shortened version, the COVID-19 fear scale (FCV-19S), and the AIS disease acceptance scale (in terms of cancer-related sensations). The questionnaire survey was conducted among patients of cancer clinics (Poland). The study was conducted in two stages–before the COVID-19 pandemic (May 2019) and during the COVID-19 pandemic (May 2020). Data from 450 correctly completed questionnaires were analyzed statistically. The obtained data were statistically processed using the Kruskal-Wallis and Mann-Whitney U test (p = 0.05).Results: Among the surveyed patients of the cancer clinic, the quality of life during the COVID-19 pandemic decreased by 2%, compared to the period before the pandemic. The frequency of negative feelings associated with cancer increased during the COVID-19 pandemic–by 11% more men, and 4.4% of women determined the frequency of negative feelings to be 2–3 times a week. The level of fear associated with COVID-19 was moderate (57.1%), with women having a higher level of fear (12.5% higher than men).Conclusion: The development of the epidemic is very important in terms of public health. COVID-19 should be considered as one of the factors that bring about sudden changes in the mental health of the population, which may result from the dynamic development of this disease, dramatic media coverage, and own experiences. It has been shown that the sudden appearance of such a large stressor causes a decrease in patients' quality of life and an increase in negative feelings associated with chronic disease. The number of cancer patients is constantly growing. Both WHO  and IARC  report that this number may reach up to 24 million new diagnosed cases over the next two decades .The WHOQOL quality of life questionnaire is self-description. It allows determining the degree of adaptation to the disease, the feeling of positive  and negative , as well as the quality of social contacts and support received. The respondent lists the factors that have the greatest influence on his or her quality of life . Based on the results of the WHOQOL questionnaire, the quality of life is assessed–from very bad to very good. Moreover, in collecting data on the frequency of negative feelings related to the disease, the following AIS scale characteristics were used: difficulty in adapting to the limitations imposed by the disease; inability to perform favorite activities; feeling of worthlessness and loneliness; feeling of dependence on the environment; feeling of being a burden for others. The respondents assessed on their basis how often a given feeling appears in their lives .Another tool used in the study was the FCV-19S scale according to Ahors (in Polish translation). Compliance with the statements  contained in the scale is scored from 1 to 5, according to the assumptions of the Likert scale, where one means disagreement with the statement and five means full agreement with the statement. The scale consists of seven sub-scales, from which a maximum of 35 points can be obtained. The final result is a percentage value , with the following verbal interpretation: 76–100% high level of fear; 56–75% moderate level of fear; 26–55% low level of related fear; <25% no COVID-19 related to fear. For the standardization test in the self-test, a Cronbach α 0.90 was obtained. The main purpose of the scale is to assess the respondent's emotions, which could indicate the level of fear or even anxiety associated with the possibility of SARS-CoV-2 infection. The reliability of the scale was confirmed in the pre-test and in other previously mentioned research projects .The data obtained were developed in Statistica 13.0 by Statsoft, using the Kruskal-Wallis and Mann-Whitney U test (n = 252) and 44% were men (n = 198). In terms of education, those with secondary education (34.2%) and vocational education (30.5%) were the largest group. Respondents with higher education were 23.8%), and those with primary education were 11.4%). In terms of education, those with secondary education (34.2%) and vocational education (30.5%) were the largest group. Respondents with higher education were 23.8%), and those with primary education were 11.4%). The most commonly reported cancer problem in this group was lung cancer (54.1%), cancer of the colon or other parts of the gastrointestinal tract (32.4%), other, including cancers of the head and neck region.The research group consisted of 450 people with diagnosed cancer, who were patients of the oncological outpatient clinic at the time of the research. The average age of the respondents was 45 ± 6 years, 56% were women (p < 0.05). The results are presented in The first research problem concerned the level of quality of life of people treated with oncology. It is assumed that the quality of life includes the physical, mental, and behavioral spheres of human functioning. The examined persons made a subjective assessment of their quality of life. The results presented in p < 0.05)–The WHOQOL questionnaire was also used in the self-assessment of the health condition of the examined patients. The obtained results indicate that women interpret their health condition worse than men . Very good and good health was characterized by an average of 3.5% and 25.0% of respondents at the pre-COVID-19 stage and 0.9 and 25.3% of respondents at the pandemic stage. It was observed that the results between the study periods differed–in the period before the pandemic the self-assessment of health condition was higher in the studied group of patients (p < 0.5) –Selected subscales from the AIS questionnaire  were used to assess the frequency of bad sensations associated with cancer. Based on the results obtained it was observed that the frequency of negative feelings associated with cancer increased during the COVID-19 pandemic . It was observed that the level of fear was higher among women (22.2 points −63.4%) than among men (17.8 points −50.8%)–4 points .With the development of the COVID-19 pandemic worldwide, attention began to be paid to the special situation of chronically ill patients–including oncological patients. This was due both to a higher risk of coronavirus infection and its complications, for this group of patients, and the abandonment of diagnosis and treatment due to limited access to medical services. When the attention of decision-makers and the public was focused on new cases of coronavirus infections, the situation of many times larger group of oncological patients remained in the shadow.According to the report “Oncology in COVID-19,”The described situations are reflected in indicators such as patients' quality of life, their feelings about the disease, and their fear of SARS-CoV-2 infection (COVID-19). In our study, we found that the quality of life during the COVID-19 pandemic decreased by 2% compared to the pre-pandemic period. The attitude to the disease also changed. Negative feelings related to the disease, such as problems with adapting to limitations, inability to perform favorite activities, feeling of worthlessness and loneliness, feeling addicted to the environment, feeling of being a burden to others; occurred much more often during the pandemic than in the period preceding it. Moreover, it was observed that the studied group is characterized by a moderate level of fear associated with COVID-19. These results are consistent with those of other researchers , with women having a higher level of fear (12.5% higher than men).The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.MGr: idea and methods. ED and EN: material. MB: redaction. MGó: methods. All authors contributed to the article and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.