The distribution pattern of ecological asset value from southwest to northeast is “high–low–high”. There is a significant positive correlation in the spatial distribution of the overall ecological assets, with similar aggregation between neighboring units. The expansion of forest land was the main factor for the rapid increase of assets from 1995 to 2010, with a contribution of 98.12%; the conversion of arable land and grassland to construction land was the main factor for the decrease of assets from 2010 to 2018, with a percentage of 81.06%, where the value of each type of service was mainly composed of five items, such as soil formation and conservation, biodiversity conservation and gas regulation, water conservation, and climate regulation. This study shows that spatial and temporal evolution assessment of ecological assets is an important manifestation of the effectiveness of rocky desertification control, which can provide decision support to resource managers and users for regional ecological environment construction.The rocky desertification control project in karst areas exacerbates the transfer of landscape types, changes the ecosystem structure and function, and has a significant impact on ecological assets. How to analyze the relationship between landscape type shifts and the spatial and temporal evolution of ecological assets is one of the key questions that need to be addressed to achieve the goal of overall improvement in ecosystem quality and sustainable regional economic development. This study takes Qixingguan District, Bijie City, Guizhou Province—a typical karst plateau mountainous area—as the research object, and analyzes the spatial and temporal evolution characteristics of landscape type shifts and ecological assets triggered by rock desertification management from 1995–2018, based on the equivalence factor method, combined with the contribution rate, spatial autocorrelation, and sensitivity research methods. The results showed that arable land, grassland, and woodland were the main landscape types in the study area. The value of ecological assets showed a trend of increasing and then decreasing, with an overall increase of 87.70 × 10 It take5 km2 . With th5 km2 , it is uEcological assets are ecosystems that provide ecological products and service benefits to humans in a certain spatial and temporal context with technical and economic conditions, including two categories of direct ecological product values  and indirect ecosystem service values  ,8,9,10, This paper applies the equivalence factor method, revises the Chinese ecosystem service value coefficient table, analyzes the land use data from 1995–2018 by remote sensing and GIS technology, explores the process of landscape type transfer in karst plateau mountains, elucidates the spatial and temporal evolution characteristics of regional ecological assets, and has important indicative significance for ecosystem protection and restoration in karst rocky desertification areas, with a view to providing a scientific basis for global karst ecological environment construction and regional economic development.2 , a central city at the junction of Sichuan, Yunnan and Qian in the northern part of the Yunnan–Guizhou Plateau, covering an area of about 3412 km2 . The limhttps://www.resdc.cn/ (accessed on 10 September 2021)) with a resolution of 30 m and a decoding accuracy of more than 90% [https://www.gscloud.cn/ (accessed on 15 September 2021)). (3) Socio-economic data: from the China Statistical Yearbook (http://www.stats.gov.cn/tjsj/ndsj/ (accessed on 23 September 2021)), the statistical bulletin on national economic and social development of Qixingguan District People’s Government of Bijie City (http://www.bjqixingguan.gov.cn/ (accessed on 11 October 2021)), and the China Agricultural Information Network (http://www.agri.cn/ (accessed on 15 October 2021)) for annual production, sown area, and prices of major grains .The data used in this paper include: (1) land use data: six periods of land use data  from the Resource and Environment Science and Data Center of the Chinese Academy of Sciences (than 90% . (2) TopAs shown in T is the time span of the study period.The average annual rate of change equation measures the rate of change of a single landscape type and is important for measuring its spatial and temporal variability , as follThe landscape type transfer matrix fully characterizes the dynamic evolutionary process of interconversion between various land types under a certain spatial and temporal condition , the rec2 in the study area to the national average grain yield of 5233.15 kg/hm2. To reduce the disturbance of spatial and temporal heterogeneity and socioeconomic fluctuations, the average food production and prices in the study area from 1995–2018 were used as the benchmark for analysis to accurately assess the impact of landscape type transfer on ecosystem service values (ESVs). Using rice wheat corn as the main grain price for calculation, a national standard equivalence factor for ESVs was derived as 2280.16 Yuan/hm2·a. Based on the table of Chinese terrestrial ESVs equivalence factors, a table of ESVs factors per unit area in the study area was converted by incorporating correction factors , The ESVs are calculated as follows ,29:(3)EaTo avoid fluctuations in the accounting results of ecosystem service value coefficients from affecting the accuracy judgment, a sensitivity index was applied to determine the dependence of ESVs on ecosystem service value coefficients over time . The exp(1)Trends in spatial pattern changesThe spatial layout of the value of ecosystem services is described in the paper using townships as the study unit, and the amount of value change is expressed using CV, calculated as follows:(2)Spatial autocorrelation analysisSpatial autocorrelation analysis is a measure of whether the distribution of spatial variables is clustered and contains both global spatial autocorrelation and local spatial autocorrelation , which wGlobal spatial autocorrelation reveals the spatial correlation of unit attribute values with neighboring units. The global Moran’s I is the widely used global autocorrelation statistical measure and is calculated as follows :(8)I=∑inp < 0.05) LISA distribution plot, calculated as follows:n is the number of spatial cells, Local Indicators of Spatial Association (LISA) is often measured using the local Moran’s I statistic, which measures the degree of similarity or difference between the observed unit attribute values and the surrounding unit attribute values, and is plotted on the basis of the z-test ELi−From 1995–2018, arable land, woodland, and grassland were the dominant landscape types in the study area, spatially, with woodland, waters, and construction land areas showing an increasing trend .During the study period, the area of forest land, construction land, and water land types increased significantly , and theIn 2 and an area of 11.77%. Cultivated land has the largest area transferred in the process of landscape type transfer, accounting for 39% of the total change area, and the main types of transfer are woodland, grassland and construction land, with a significant increase in the area of woodland, accounting for 45.28% of the total area transferred from cultivated land; grassland follows in the transfer process, mainly transferred to woodland, cultivated land and construction land, with an increase in the area of woodland accounting for 53.84% of the total area transferred from grassland, with cultivated land. The interconversion activities between cropland and grassland were intense and the total area transferred was very close. Forest land is the main type of conversion from other land types, accounting for 38.51% of the total changed area, and the conversion of grassland to forest land is the most, accounting for 54.56% of the total converted area of forest land; the converted area of cropland is the second, accounting for 34.23% of the total changed area, of which the converted area of forest land to cropland is the most, with a conversion rate of 54.72%.From 1995–2018, 25 landscape types were transferred in the study area , with a As shown in , the mid6 yuan before 2000, increasing by 27.09 × 106 yuan in the next 5 years, and decreasing by 38.32 × 106 yuan after 2005, for a cumulative decrease in total ESVs of 18.59 × 106 yuan. The change trend of increasing ESVs was similar for woodland and watershed, but from 2010 to 2018 woodland ESVs decreased by 7.14 × 106 yuan and watershed remained largely unchanged, with woodland and watershed ESVs increasing by 211.36 × 106 yuan and 1.8 × 106 yuan, respectively, during the study period. Grassland ESVs showed a continuous decreasing trend with a cumulative decrease in ESVs of 100.3 × 106 yuan. The decrease in ESVs of unused land maintained a stable state until 2000, with a decrease of 0.04 × 106 yuan.Under the influence of the overall landscape type shift, as shown in , the cha6 Yuan, an increase of 2.7%; after that, cropland, forest land and grassland all showed a decrease, much higher than the increase of water bodies, showing a gentle decreasing trend, with a total decrease of 41.32 × 106 yuan and a decrease rate of 0.65%. The total value of ecosystem services increased by 87.70 × 106 yuan during the study period, with a growth rate of 1.41%. The period between 2005 and 2010 was the period of more drastic changes in the value of forest land, grassland, watershed, and cropland, and also the period of the largest increase in total ESVs. In conclusion, the increase in the area of forest land was the main reason for the increase in value until 2010; after that, the decrease in the area of grassland and cropland was the main reason for the decrease in value.The trend of the total ecosystem service value in the study area was to increase first and then decrease, and the increase of the service value of forest land and cropland was much higher than the decrease of grassland up to 2010, showing a significant increase trend, and the total ESVs increased by 129.02 × 10As shown in , for difThe spatial and temporal trends of ESVs are characterized by using township geographical units, and the service values per unit area are graded at equal intervals by GIS spatial statistical techniques, divided into six stages, and graded by specific color fields to present the differential changes of ecosystem service values of different units. From 1995 to 2018, the ESVs in the northeastern part of the study area were higher a,b, and (1)Global spatial autocorrelationp < 0.05)  , ESVs in(2)Local spatial autocorrelationThe spatial distribution of EVSs has a large and significant correlation, and local spatial autocorrelation analysis was carried out to clarify the types and specific locations of regional aggregation characteristics. From  local spFrom 2010 to 2015, local (H-L) aggregation of ESVs occurred in the town of Cengtai and (L-H) in the town of Haizijie, and the trends of ESVs between the two geographical units were independent of each other, indicating that the autocorrelation of the local units was not significant. A shift in the local (H-H) aggregation of ESVs between Xiaojichang town and Liangyan town to non-significant occurred in 2018, indicating that this type of unit does not have spatial autocorrelation.6 yuan, with the largest contribution from grassland to woodland, followed by cropland to woodland. Meanwhile, the 13 landscape shifts that occurred resulted in a decrease in total ESVs of 240.39 × 106 yuan  showed a decreasing trend ; the valThe main landscape types in the study area are arable land, forest land, and grassland, which show the interconversion of arable land, forest land, and grassland, and the main transfer processes such as the conversion of arable land to construction land, which differ greatly from the results of global and national studies on the conversion of arable land to forest land, grassland, and construction land ,35. LimiEcological assets in the study area show a spatial distribution pattern of “high–low–high” from the northeast to the center of the city due to the expansion of urban land and rapid economic development, coupled with ecological migration driven by policy reasons , which tDuring the study period, the Moran’s I table of ESVs across the region changed, indicating that the regional ESVs suffered from external disturbance factors and the clustering stability was weak, and a large amount of resources were invested in implementing precise poverty alleviation policies to eliminate absolute poverty , which iThe results of the study showed that the conversion of grassland and cropland to woodland contributed the most to the increase in regional ecological asset value, with an overall average contribution of 68.46% for woodland, and that woodland expansion on grassland and cropland has become the dominant landscape type , which iThis study suffers from the homogenization of remote sensing data, the degree of regional landscape fragmentation, and the blurred boundaries of each ecosystem type, resulting in the failure to clarify the transfer mechanism of secondary ecosystem service functions, negative service types, and system quality change patterns. The analysis of only natural landscape types may also cause a decrease in the accuracy of ecological asset value assessment. Therefore, we can strengthen the analysis of the impact of future intensification and structural transformation of landscape types on ecological assets, and need to establish a multi-factor-driven evaluation index system and methodological research on the spatial and temporal changes of ecological asset values, and identify the main control factors affecting services and functions and accurately assess the value of different landscape types. In this way we can lay the foundation for rational planning of ecological functional areas in the study area and assessing the effectiveness of ecosystem protection under rock desertification control.Qixingguan District, Bijie City, Guizhou Province, is a typical representative of karst plateau mountains, and it is important to analyze the influence of its landscape type shift on the spatial and temporal evolution of ecological assets for the construction of karst ecological environments and regional economic development. The methodological analysis of sensitivity, spatial autocorrelation, and contribution rate showed that: (1) The three main landscape types of arable land, woodland, and grassland transform drastically and change the structure and function of the local ecosystem. (2) In time, the value of ecological assets showed a trend of increasing and then decreasing, and the expansion of woodland and the decline of grassland were the main reasons for their value fluctuations. (3) The overall spatial distribution of ecological assets has a significant positive correlation, and similar aggregation exists between adjacent units as a whole; local units have significant spatial differentiation characteristics. (4) Among the different landscape types shifted, the continuous expansion of woodland has the highest contribution to the value of ecological assets.This paper carries out the spatial and temporal dynamic analysis of ecological asset value by using remote sensing follow technology, and clearly presents the spatial and temporal evolution mechanism of ecological assets based on the perspective of landscape type transfer. The interrelationship between different landscape types and different functions is analyzed through the dynamic change pattern of ecological asset value, exploring a new idea of clarifying the main control factors of regional ecological assessment and expanding the application framework of ecological asset accounting in ecological benefit assessment. It provides scientific basis for decision makers to reasonably plan landscape types and has important reference value for karst ecosystem restoration management, optimization of ecosystem service functions, and consolidation of stone desertification management effectiveness.


The cementation and filling action of hydrates resulted in the transformation of large pores into smaller ones, hence the optimal pore size decreased with an increasing curing period and cement content. The stress–strain curves and hydraulic conductivity were determined based on unconfined compression and flexible wall penetration tests, respectively. The unconfined compressive strength increased exponentially with the amount of combined water, and the functional correlations of hydraulic conductivity and micropore parameters were established. The reliability of the NMR technique as a new method to study the microscopic evolution mechanism of the strength and permeability of CDS was further verified by scanning electron microscopy and mercury intrusion porosimetry tests.Cement-stabilized dredged sediment (CDS) when used as a new road construction material cannot only solve the problem of abandoned sediment disposal, but also effectively save natural soil resources. This study aimed to evaluate the strength and permeability of CDS and establish corresponding prediction models from the perspective of a stabilization mechanism. The soil–water composition and pore size distribution were investigated by the nuclear magnetic resonance (NMR) technique. The results demonstrated that more liquid pore water inside the CDS specimen transformed into combined water with cement hydration. The amount of combined water, which essentially characterized the hydration process of cement, presented a linear relationship with log ( Large quantities of sediments are dredged annually from harbors, waterways, and lakes to build port facilities, maintain shipping capacity, or protect water environment ecology ,2,3. TheCement stabilization of dredged sediment involves following three aspects ,19,20: (T2) of the proton, and the T2 distribution curve of pore water in the samples can be obtained by Fourier transformation [T2 of liquid water was calculated as Equation (1),ρ2 is the transverse relaxation rate, a parameter characterizing the property of porous material, and S and V represent the surface area and volume of the pores where liquid water resided, respectively. When considering the pore as a cylindrical shape, Equation (1) can also be abbreviated as,R was the pore radius. Equations (1) and (2) show that the T2 value is proportional to the pore radius R, that is, a higher value of T2 represents a larger pore size [T2 distribution curve can reflect the distribution of pore water and pore size in the porous media, and the peak area below the curve represents the corresponding water content [Recently, nuclear magnetic resonance (NMR) technology has been applied to detect water distribution and pore structure characteristics in the field of geotechnical engineering. Yu et al.  confirmeormation . In a unore size . Therefo content .Strength and permeability are the key performance parameters to evaluate the use of CDS as road building materials. This study aims to investigate the mechanism of water transformation and pore structure evolution during cement stabilization by the NMR technique and to establish a quantitative relationship between macro-geomechanical properties and microstructure. A series of laboratory specimens were prepared for different cement contents and curing periods. Furthermore, the stress–strain curves were determined based on an unconfined compression test, and the effect of the water content parameters on the strength development was quantitatively evaluated from the perspective of the stabilization mechanism. Similarly, mathematical models for evaluating the relationship between hydraulic conductivity, which are measured by a flexible wall permeameter and the representative parameters for pore size distribution, were proposed. Finally, the reliability of the NMR technique as a new method to study the microscopic evolution mechanism of strength and permeability of CDS was further verified by scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) tests.The dredged sediment used in this study was taken from the bottom of a river in Suzhou, China. The sediment collected from the site was first sieved to remove impurities with a large particle size. The basic physical properties of dredged sediment are shown in T2 distribution curves were drawn. Based on the NMR theory: (1) the integral area under the T2 distribution curve (termed as the “peak area”) represents the total population of pore water molecules in the T2 range; (2) the horizontal coordinate of the curve (transverse relaxation time T2) represents the size of interstitial pores saturated with water; and (3) the “T2 at peak (TP2)” refers to the T2 value corresponding to the maximum NMR signal, thereby representing the optimal aperture [The FID curves of the CDS specimen were determined using the Carr-Purcell-Meiboom-Gill technique with a 23 MHz NMR setup . The schThe unconfined compression test (UCT) was carried out by a hydraulic servo testing machine at a vertical loading rate of 1 mm/min, which was terminated when the peak strength of the specimen was attained or 8% of its axial strain was reached. The average value of three specimens was taken as the final unconfined compressive strength (UCS). The hydraulic conductivity testing (HCT) was carried out with the flexible wall permeameter. The specimen was vacuumized for 30 min and then saturated with deionized water for 24 h before the test. During the test, the confining pressure was kept at 200 kPa, and the osmotic pressure difference was kept at 100 kPa between the upper and lower ends of the specimens.The micromorphology of CDS was observed by using scanning electron microscopy . The pore structure was characterized by performing a mercury intrusion porosimetry (MIP) test, which can achieve a maximum pressure of 227 MPa. Sample pieces for microscopic analysis were immediately pre-treated with liquid nitrogen freezing and vacuum drying for 48 h. Furthermore, the blocks used for MIP and SEM analysis were taken from the undisturbed parallel CDS specimen to exclude the influence of micro-damage caused by external factors.T2 distribution curves of three groups of specimens with different cement contents during the curing period were depicted in T2 distribution curves of all the specimens showed a bimodal distribution (primary peak and secondary peak) and spanned several orders of magnitude (0.01–10 ms). Since the pore size is proportional to relaxation time T2, the bimodal distributions indicated the existence of macro- and micro-pores within the CDS matrix. The T2 curves of the three groups of CDS specimens all shifted to the lower left with an increasing curing period. That is, the total peak area, the T2 at peak (TP2), and the maximum NMR signal gradually decreased, which denoted that the liquid PW inside the CDS specimen transformed into CW with cement hydration. At the same time, the proportion of large pores decreased and that of the small pores increased, and the distribution of internal pores became relatively uniform.The T2 distribution curves of three groups of CDS specimens at the 28-day curing period are plotted in TP2 decreased gradually with increasing cement content. However, the main peak of the T2 distribution curves was on the left for the specimen with 5% and 10% cement, while that of the specimen with 15% cement was opposite, implying that the internal pore structure of CDS specimens changed significantly. Therefore, with the increase of cement content, more liquid PW was involved in cement hydration and transformed into CW, and the optimal pore size decreased while the proportion of small pores increased.To highlight the influence of different cement contents more clearly, the Since the CDS specimens were in sealed condition, the reduced liquid PW mass was exactly equal to the mass of generated CW. Given this, the corresponding water parameters were calculated as follows:mpws) and the corresponding total peak area of the T2 distribution curve (As) were taken as the reference. Then, the PW mass corresponding to the unit peak area (upw) was calculated:(I) The untreated dredged sediment with a known initial water content was taken as the standard sample, and its PW mass (T2 distribution curve of each CDS specimen (shown in Ai), then the PW mass of each CDS (mpwi) was calculated:(II) The shown in  was intempw0) and the PW mass (mpwi) of each CDS specimen was the CW mass generated by the hydration reaction (mcw):(III) The difference between the initial PW mass (Q(t)/Q(max), Q(t) was the hydration heat at time t, and Q(max) was the complete hydration heat. The model in this study indirectly represented the hydrates production in the CDS specimen from the perspective of water transformation, while mcw, α, or Q(t) were all essential parameters that characterized cement hydration progress and all the presented linear relationships with log (t), which effectively proved the reliability of NMR technology in exploring the mechanism of water transformation in CDS. Moreover, it can be found by fitting the data in TP2 with mcw also follows a power function form of y = axb, which indicated the optimal pore size decreased with cement hydration, shown in ρ2, of CDS is chosen as 0.22. Then, the cumulative pore size distribution curve can be obtained by calculating the T2 distribution data in D50 is the median entrance throat diameter when the cumulative total pores reach 50%, which can be selected as a representative indicator to characterize the pore structure characteristics of the CDS matrix [D50 of specimens with 15% cement was 0.29, 0.14, 0.13, 0.10, and 0.09 µm for 1, 3, 7, 14, and 28 days, respectively, thereby indicating that the average pore size gradually decreased with the curing period. Furthermore, based on the feature and shape of the pore size distribution curve  of specimens with 5% and 15% cement after 28 days of curing were compared with the pore size distribution determined by NMR, which is shown in mcw, as shown in mcw may be a suitable parameter to reflect the structure formed by the interaction between hydrates and soil aggregates in CDS. Therefore, it is necessary to further explore the quantitative relationship between the strength and water distribution of CDS.qu/qu−28d) can be obtained by dividing the strength of a particular curing time by the 28-day strength. In addition, the relationship between the normalized strength and curing period can be expressed by the following formula for specimens with different cement contents in this study . The fitting results are of very good quality as indicated by the high coefficient of determination (R2 > 0.96). The inevitable scatter of the normalized qu data may be due to the variability of UCT specimens at different curing ages.The strength development with curing time is shown in udy vide .(6)qu/qk from 7 days to 28 days , mainly explore the cement stabilization mechanism from the perspectives of micromorphology, pore structure, and mineral composition. However, the deficiencies of these methods are as follows: (1) The integrity and initial structure of the original specimen are inevitably damaged by the complex pretreatment, such as the freeze-drying process in the SEM and MIP tests; (2) a small amount of test sample taken locally (tens of micrograms or a few grams) may not be adequately representated, such as the powder sample used in XRD and TGA experiments; (3) the hydration process of the test specimen is forced to stop, making it difficult to carry out continuous tests on the same specimen throughout the curing period; and (4) the number of hydrates generated inside a specimen cannot be measured accurately, hence the essential relationship between the geomechanical behaviors and hydration reaction cannot be constructed quantitatively. In contrast, the NMR technology is used to test a full-size initial specimen directly, without any pretreatment that may cause microdamage inside the specimen. Furthermore, the NMR test can be carried out for the whole curing period of the same specimen, and each measurement only lasts for several minutes. The hydration progress can be accurately tracked by monitoring the conversion of pore water and combined water, and the pore structure characteristics can be deduced from the (1)T2 at peak gradually decreased with an increasing curing period and cement content, indicating that more liquid pore water inside the CDS specimen transformed into combined water with cement hydration. The amount of combined water, mcw, which essentially characterized the hydration process of cement, presented a linear relationship with log (t).The total peak area and the (2)k and micropore parameters D50 were established.The cementation and filling action of hydrates resulted in the transformation of large pores into smaller ones, then the proportion of mesopores and macropores gradually decreased with the curing period. In addition, the characteristics of the pore size distribution curves determined by the MIP and NMR were highly consistent. Given that there was an essential relationship between permeability and pore size distribution, the functional correlations of hydraulic conductivity (3)qu/qu−28d and curing period t can be characterized by a linear function.With the increase in the curing period, more hydrates contributed to the denser and firmer microstructure within the solidified matrix, and the stress–strain characteristic of CDS specimens changed from ductility to brittleness. Furthermore, the relationship between the normalized strength (4)mcw can comprehensively characterize the influence of the curing period and cement content on the strength development of CDS from the view of a stabilization mechanism and qu increased exponentially with mcw. The microstructure characteristics measured by SEM revealed the evolution mechanism of strength and permeability more intuitively.The parameter (5)In the actual project of filling subgrade with CDS, increasing cement content can improve the strength and reduce hydraulic conductivity in a short term, which is helpful to promote the progress of some special projects with tight construction periods. In general, the curing period should be extended to at least 28 days, which is conducive to the full hydration and stabilization effect of cement.


The markers of lipid peroxidation, antioxidant capacity, electrophoretic mobility of erythrocytes (EPM), aggregation, levels of adenosine triphosphate (ATP) and 2,3-diphosphoglyceric acid , hematological parameters were estimated in RBCs. An increase in EPM and a decrease in the level of aggregation were observed in groups with multiple and single H2 application. The orientation of lipoperoxidation processes in erythrocytes was combined with the dynamics of changes in oxidative processes in blood plasma, it was observed with both single and multiple exposures, although the severity of the changes was greater with multiple H2 inhalations. Probably, the antioxidant effects of molecular hydrogen mediate its metabolic action. Based on these data, we conclude the use of H2 improves microcirculation and oxygen transport function of blood and can be effective in the treatment of CHF.Molecular hydrogen has an anti-inflammatory and cardioprotective effect, which is associated with its antioxidant properties. Erythrocytes are subjected to oxidative stress in pathologies of the cardiovascular system, which is the cause of a violation of the gas transport function of blood and microcirculation. Therefore, our aim was to investigate the effects of H Chronic heart failure (CHF) is a complex syndrome that occurs as a result of structural and functional disorders affecting the ability of the heart to supply oxygen to tissue. Heart failure is the leading cause of morbidity and mortality and causes high health-related costs .Despite the achievements of modern medicine, the prevalence and hospitalization of patients with this pathology increases annually. This is due to the current improvement of the treatment of other cardiovascular diseases , population aging and comorbidities and additional chronic diseases . TherefoHypoxia, accompanied by increased oxygen consumption, is a trait common to the development of chronic heart failure syndrome caused by various etiologies. Pathophysiological mechanisms of heart failure development include inflammation, myocardial injury, fibrosis, oxidative stress, hypertrophy and neurohormonal activation, which cause hemorheological disorders and inadequate blood flow in CHF .Red blood cells (RBCs) provide the delivery of oxygen to tissues to meet metabolic needs  and are 2). H2 has antioxidant, anti-inflammatory and anti-apoptotic properties [2 caused an improvement in ischemia/reperfusion injuries of the brain [Ischemic injuries resulting from hemodynamic changes provoke oxidative stress and, as a consequence, a change in the mechanical properties of erythrocytes, a decrease in their deformation, an increase in adhesion to the vascular wall. The result of these processes is hypoxia of tissue . Over thoperties ,10. It hhe brain  and in mhe brain .2 in various diseases associated with increased oxidative stress. The cardioprotective effects of molecular hydrogen in patients were confirmed, which was associated with H2 antioxidant properties [https://openheart.bmj.com/content/5/2/e000814 (accessed on 15 December 2007) [Numerous publications of preclinical and clinical studies have demonstrated the beneficial effects of Hoperties . Oxidatier 2007) . However2 inhalation on the functional states of RBCs in chronic heart failure in rats.Based on these previous studies, the objectives of this study were to investigate effects of Hn = 30) weighing 260 ± 20 g were obtained from SPF-vivarium of Laboratory Animals Genetic collections Center (LAGCC) . Rats were acclimated for one week in plastic cages. Animals were raised under standard laboratory conditions , food and water without restrictions. The study was performed in accordance with guidelines for animal research (ARRIVE guidelines 2.0) [The research was approved by the Local Ethics Committee for conducting scientific research involving animals as research objects of the Lobachevsky State University on 9 October 2020, and conducted following the European Community guidelines . Male Wistar rats (nes 2.0) .CHF was induced as previously described  by intraHistological studies of the rat’s heart indicated the presence of pathognomonic changes for CHF. Along with normal cardiomyocytes, there were destructive and hypertrophied forms, the nuclei were wrinkled, deformed, reduced in size, hyperchromic, displaced to the cell periphery, a plethora of vessels, pronounced infiltration and signs of fibrosis were also observed. Histomorphometry was estimated by the μvizo 103 transmitted light micro-imager (“LOMO”) at magnifications of 20× and 40×.n = 10) in each group. In the 1st research group, the animals were placed in ventilated boxes (24L) connected to the hydrogen gas generator  and admitted to spontaneous breathing  for 40 min a day for 5 days in a row. The portable gas analyzer of explosive and toxic gases and vapors “Hydrogen (H2)”  was installed in the box to control the concentration of gases. In the 2nd research group, rats breathed a gas–hydrogen mixture (2% H2) for 40 min once (the day after the CHF simulation) then air was supplied to the box for the next 4 days. In the control group, rats were placed in the box and fresh air was ventilated continuously for the same duration as the hydrogen inhalations exposure time.The day after the CHF simulation, the experimental animals were randomly divided into three groups with ten rats  . To deteAn effective method to assess microcirculation disorders is to assess the aggregation of erythrocytes under microscopy of dilute blood in the Goryaev’s camera  . The degThe main energy parameter is the concentration of ATP in red blood cells. The evaluation of this indicator in the suspension of washed erythrocytes was carried out by the presence of inorganic phosphorus (Pi) in hydrolyzed erythrocytes on a photometer photoelectric KFK-3 -“ZOMZ”  at a wavelength of 660 nm using the non-enzymatic method described by us earlier .2PO4.Glycolysis of erythrocytes differs from other cells in the production of a significant amount of 2,3-DPG, which is a heterotropic allosteric modulator of hemoglobin binding to oxygen and, as a consequence, a regulator of tissue gas exchange. The concentration of 2,3-DPH was also determined by the non-enzymatic method by the increase in inorganic phosphate in the supernatant of hemolyzed erythrocytes (Pi1) and after ashing (Pi2) according to the calibration curve, in a standard solution of KHThe concentration of 2,3-DPG was measured using the following equation:Colored trimetin complex with maximum absorption at a green light filter was used to determine the concentration of MDA expressed in nmol/mL of erythrocytes . The resThe lipid peroxidation products concentration was determined by the absorption of a monochromatic light flux in the ultraviolet region of the spectrum by a lipid extract. The amount of diene conjugates (DC), triene conjugates (TC) and Schiff bases (SB) are extracted in heptane-isopropanol fractions. Measurement of optical densities (E) was performed on a SF-2000 spectrophotometer . DC, TC and SB concentration was calculated from the relative values of E232\E220, E278\E220, E400\E220 and in relative units.2O2 converted by the enzyme per unit time (min) in mg of hemoglobin (Hb)—μmol/gHb × min. Catalase activity was calculated using an extinction coefficient of the test sample immediately (E1) and 20 s after adding H2O2 (E2): The antioxidant capacity was determined spectrophotometrically by measuring the catalase activity using the method of Beers and Sizer  and exprThe study of hematological parameters was carried out on the hematological analyzer “Abacus Junior” 30ND , the number of red blood cells (RBCs), the hemoglobin concentration (Hb) and the average volume of erythrocytes (MCV) were determined.t-test. Statistical analysis was estimated using the BIOSTAT  and Microsoft Excel for Windows (MS Office 2016 (16.0.5266.1000), MSO (16.0.5266.1000), Version 64, Santa Rosa, CA, USA) application software packages using one-dimensional statistics methods.Data are presented as arithmetic mean values and standard deviations. The distribution was checked for compliance with the normal law by calculating the Kolmogorov–Smirnov criterion. It was revealed that for all the studied indicators, the type of distribution of the data obtained corresponds to normal, and therefore the subsequent analysis for determining statistically significant differences was carried out using the Student’s 2 caused an increase in EPM relative to the control group at all stages of the study. At the same time, on the first and third days, single and repeated exposure to H2 determined the same type of action and an increase in EPM by 29–34% of the values of the control group. On the 7th and 14th day of the study, the increase in EPM was more pronounced with repeated exposure and amounted to 58–34% comparatively to the control group, respectively, whereas with a single exposure, the severity of the changes was less, although it remained higher than the control group  as a marker of oxidative stress and catalase activity which serves as one of the main enzymes of the antioxidant system. MDA and catalase are present in erythrocytes in sufficiently high concentrations that can be easily measured in most laboratories, providing valuable information about the oxidative stress. MDA concentration decreased in both Hstration . Catalas3 and 14 .2, although the severity of the changes was greater in the first research group (The orientation of the processes of lipoperoxidation in erythrocytes was combined with the dynamics of changes in oxidative processes in blood plasma. Our study indicates the reduction in Schiff bases (SB) from the third day of research in groups receiving molecular hydrogen therapy. At the same time, the dynamics coincided with both single and multiple exposures to Hch group .2 led to a decrease in these indicators on the first day in both groups with H2 inhalations , hemoglobin (Hb) and the mean corpuscular volume (MCV) showed that the use of Halations . On the In this study, we compared how different duration of inhalations of molecular hydrogen affects changes in the functional state of erythrocytes. Decline of red blood cell parameters was observed in the group of rats with simulated CHF: erythrocyte aggregation increased, and the mean corpuscular volume increased. These changes can lead to circulatory disorders, impaired blood oxygenation in capillaries, decreased oxygen transport function of blood and oxygen starvation of tissues increased. Aggregation of erythrocytes prevents the entry of cells into narrow capillaries and promotes their shunting through wider vessels, bypassing capillary networks , which i2. It is possible that under the action of H2, the structure of erythrocyte membranes stabilizes due to a decrease in lipoperoxidation processes. In our experimental model, this fact is reflected in a decrease in the concentration of MDA in red blood cells. Application of H2 by inhalation contributes to reduce oxidative stress and reduced myocardial damage [2 does not affect other ROS which play an important role in maintaining cell REDOX balance and cell function [2 in our study led to an increase in the ATP concentration in erythrocytes. In return, the surface charge of erythrocytes plays an essential role in the mechanism of aggregation of erythrocytes. . Decreasl damage . The actl damage . Moreovefunction ,11. In afunction . It is pfunction . The useThe ATP formed during glycolysis serves primarily as a substrate of Na(+)/K(+)—ATPase and Ca(2+)—ATPase, which support the membrane potential of erythrocytes to preserve the integrity of the membrane and the biconcave shape of RBCs, ensuring normal functioning and oxygen transport function. It has been shown that an increase in calcium concentration enhances aggregation, changes intermolecular interactions, transforms the shape of erythrocytes due to the inclusion of the calcium signaling pathway and dephosphorylation of key proteins of the membrane cytoskeleton ,33,34. T2, processes develop in erythrocytes that optimize their rheological properties, which is necessary for adequate micro- and macrocirculation of blood. It should be noted that the deformation of erythrocytes can promote the release of both NO [2, but also about its metabolic and antihypoxic effects.Apparently, under the application of H both NO  and ATP  both NO , which c both NO . Nitric  both NO ,41. In t both NO . Through2, it is necessary to consider not only its direct, but also its indirect effect, since the effects of H2 in our study manifest themselves on the 14th day, a considerable time after the H2 inhalation. It has been shown that molecular hydrogen specifically neutralizes not only the hydroxyl radical (•OH), which has a high cytotoxic effect, but also peroxynitrite (ONOO−) [2) or nitrosolated (-S-NO2). Thus, the reduction of these factors can control gene expression [Discussing the mechanisms of action of H (ONOO−) ,42. A vapression . In addipression . During pression . The results of the experiments suggest that the stress reaction progresses with the development of CHF, which manifests itself in a decrease in EPM. The degree of changes in EPM in simulated CHF might correlate with the involvement of stress-implementing systems of the body. Molecular hydrogen seems to be able to increase the body’s resistance by limiting the stress reaction.Considering activation of the sympathoadrenal system (SAS) ,47 and h2 leads to an increase in EPM, ATP concentration, 2,3-DPG and a decrease in the level of aggregation and lipoperoxidation, which is probably explained both by the antioxidant effect of H2 on the processes occurring in erythrocytes, and by the indirect action of molecular hydrogen through the restriction of the stress reaction, as evidenced by the change in EPM.Thus, in our study, we demonstrate that the effect of inhaling H2 has a beneficial effect on the surface charge, metabolism and aggregation of red blood cells, which improves microcirculation and oxygen transport function of blood and can be effective in the treatment of CHF. Furthermore, our study could be useful in developing new therapeutic methods that include using molecular hydrogen in cardiovascular diseases. Further research should focus on evaluating the effect of molecular hydrogen depending on the duration of use and the number of inhalations.In conclusion, according to the results obtained, it can be said that the use of H


Global mitigation strategies to tackle the threat posed by SARS-CoV-2 have produced a significant decrease of the severity of 2020/21 seasonal influenza, which might result in a reduced population natural immunity for the upcoming 2021/22 influenza season. To predict the spread of influenza virus in Italy and the impact of prevention and control measures, we present an age-structured Susceptible-Exposed-Infectious-Removed (SEIR) model including the role of social mixing patterns and the impact of age-stratified vaccination strategies and Non-Pharmaceutical Interventions (NPIs) such as school closures, partial lockdown, as well as the adoption of personal protective equipment and the practice of hand hygiene. We find that vaccination campaigns with standard coverage would produce a remarkable mitigation of the spread of the disease in moderate influenza seasons, making the adoption of NPIs unnecessary. However, in case of severe seasonal epidemics, a standard vaccination coverage would not be sufficiently effective in fighting the epidemic, thus implying that a combination with the adoption of NPIs is necessary to contain the disease. Alternatively, our results show that the enhancement of the vaccination coverage would reduce the need to adopt NPIs, thus limiting the economic and social impacts that NPIs might produce. Our results highlight the need to respond to the influenza epidemic by strengthening the vaccination coverage. The worldwide fight against the threat posed by the Severe Acute Respiratory Syndrome-Coronavirus-2 disease  during the 2020/21 season , with nuIn the light of this, influenza vaccination can cover a key role in limiting the diffusion of seasonal influenza infection, as well as in avoiding the overwhelming of healthcare systems that are already under pressure , 10. RecAs suggested by recent studies e.g., , 20), th, th20]),This paper aims to explore a wide range of influenza epidemic scenarios for the season 2021/22 in Italy by taking into account the impact of single and multiple control and prevention measures in the spread of the disease for different seasonal severity. The characteristics of the epidemic scenarios are assessed through an age-structured deterministic Susceptible-Exposed-Infectious-Recovered (SEIR) epidemiological model, suitably extended in order to properly model age-structured social mixing and the impact of the control and prevention measures. The investigation of these scenarios is crucial for policymakers to infer the impact of implementing measures and to assess whether vaccination campaign strategies need to be revised to successfully lessen the public health burden.The paper is structured as follows: Section 2 describes the SEIR epidemiological model and the explored scenarios. Results are presented in Section 3, followed by discussions in Section 4. Finally, the concluding remarks are drawn in Section 5.We develop an age-structured deterministic compartment model based on the well-known SEIR model , 30, oriThe social mixing of age-structured population in our model is captured through the use of a realistic model of mixing patterns computed from routinely collected socio-demographic data of the Italian population  . Moreover, the model discriminates between different severity of illness for infected individuals by taking into account moderate cases, defined as infected individuals that require a treatment by General Practitioners (GP) or in Emergency Rooms (ER) and life-threatening cases that require Intensive Care Unit (ICU) treatment. We investigate the characteristics of seasonal influenza without distinguishing between the specific subtypes of influenza virus. However, as described below, the parameters of the model are computed by averaging epidemiological characteristics of two influenza virus subtypes, i.e., H1N1 and H3N2, which are the main subtypes causing seasonal influenza .i = 1,…,4,:We assume a population made of individuals subdivided into the following mutually exclusive seven compartments for each age class Si): individuals able to contract the flu,Susceptible (Ei): susceptible which have been exposed to contagious (exposed and infected) individuals and are able to infect,Exposed (Ii): infected individuals,Infected (Gi): infected individuals being treated by general practitioners or in emergency rooms,GP/ER treated (Ti): infected individuals requiring critical medical care in ICU,ICU treated (Ri): individuals removed from the epidemic dynamics by recovering or by getting the vaccination,Recovered (Di): individuals passing away due to the flu.Deceased  introduced above and Mij indicates the contact matrix (see Sect. 2.2), defined as average number of daily contacts between an individual in age class i with an individual in age class j, where i, j = 1,…,4. The lower-case letters denote the transition rates and the fraction of individual moving between different compartments, defined as follows:We consider closed age classes with no births and natural deaths, such that the population number βi is the probability of disease transmission (see Sect. 2.4) in a single contact between a susceptible in age class i and a contagious individual (exposed or infected). We assume that exposed individual can transmit the virus at early stages before symptoms develop, as confirmed by epidemiological investigations ;pi is the susceptibility to infection, taken from [ken from , Chapterσ denotes the rate at which individuals move from exposed to infected, while γ is the rate of transition from the compartment of the infected to the compartments of GP/ER treated, ICU treated or recovered. Their values are related to the incubation time tσ = σ−1 and the remission time tγ = γ−1, assumed to be equal to 1.5 and 4 days respectively [ectively –40;ai denotes the fraction of infected individuals being treated by general practitioners or in emergency rooms, while bi is the fraction of infected individuals requiring critical care in ICU. The reference values of these parameters have been taken from [ken from –44;ci is the vaccination coverage, defined as the fraction of susceptible that get the vaccination. The reference values for the vaccination coverage ciref, are taken from [ken from  (see Secϵi(t) is the time evolution of the vaccine effectiveness, computed by analysing the results reported in [orted in   for the state variables: Si(0) = Ni−1000, Ii(0) = 1000, while the rest of state variables are null. We run the simulation of the epidemic over a time period of 100 days, which can be considered a representative period for the duration of seasonal flu epidemics.The integration of the Eqs ij is computed as a linear combination of four contact matrices related to the expected mixing patterns in different physical environments , i.e.,αK are the setting-specified coefficients of the linear combination [δK indicates the corrective factors introduced here to model the adoption of NPIs (see Sect. 2.4). For the purpose of our work, since the impact of the NPIs in the epidemic dynamic are environment specific, we compute the coefficients αK of the linear combination by analysing data provided by [αH = 0.29, αS = 0.17, αW = 0.24 and αG = 0.3. These coefficients will be scaled according to the expected impact of the adopted NPI in the mixing patterns, as described in Sect. 2.4. Our model incorporates the impact of social mixing patterns see Eqs  and 2 bybination  and δK ivided by . The resϵi(t), see Eqs R2~0.99 . These measures are described as follows:δS = 0.5,school closures: reduction of contacts at school by 50%, i.e., δS = δW = δG = 0.2.partial lockdown: reduction of contacts at school, work and in the general community to 20%, i.e., δK are assumed equal to unit values, with K = 1,…,4. Furthermore, we explore two additional scenarios to infer the impact of different Vaccination Coverage (VC) with respect to the reference case . In thith day after the beginning of the epidemic. The key advantage of this approach is to analyse the relative trend of the epidemic evolution among different scenarios in order to figure out the impact of the different NPIs and vaccination campaign strategies and compare the effect of each measure in terms of the reduction of the number of infected and deceased individuals.In this Section we present outcomes of the epidemic dynamical simulations for the set of scenarios described above (see Sect. 2.4). The analysis is aimed at inferring the effectiveness of control and prevention measures in the mitigation of the epidemics. In order to characterize the outcome of the epidemic spread in the different scenarios, we will focus on the time evolution and the cumulative number of the infected and deceased individuals with respect to the number of individuals at the end of epidemics. It is worth remembering that the end of epidemics is assumed to be the 100In In order to evaluate the overall effect of vaccination, we compute the cumulative fraction of infected and deceased individuals at the end of the epidemic for each age class. As expected, the impact of standard vaccination is stronger for elderly people (age ≥ 65 years), reaching an average reduction over the three scenario of season severity of ~88% of the infected and deceased population with respect to the scenario without vaccination, while the reduction of infected and deceased non-elderly subjects reaches values of ~73% for those aged 15–64 years and of ~55% for infants and children. This is due to the relatively larger vaccination coverage for elderly subjects see . MoreoveBy computing the cumulative fraction over all age classes, mild season epidemic evolution with standard VC shows similar results among all age classes compared to the one with enhanced coverage, with a cumulative fraction of infected people of around ~0.08% and ~0.06% with standard and enhanced coverage, respectively  to ~44% of the total population, while the enhanced coverage produces a further reduction up to ~6.4%.In this Section we compare the impact of the adoption of single NPIs in the mitigation of the spread of disease with respect to the vaccination in moderate and severe seasons, taking into account, additionally, the combined effect of NPIs and vaccination. Moreover, the impact of the enhancement of the VC is similar to the effect produced by the standard vaccination and school closures  influenza seasons, the impact of school closure leads to a reduction of the fraction of infected and deceased population by a factor ~2.3 (~1.5) for individuals aged less than 5 years, a factor ~2.8 (~1.7) for those aged 5–14 years, a factor ~ 1.7 (~1.4) for individuals with age in the range 15–64 years and any reduction among the elderly with respect to the scenario without the adoption of any NPIs.Moreover, partial lockdown mitigates the spread of moderate (severe) seasonal influenza epidemics by reducing the fraction of infected and deceased individuals by a factor ~73 (~12) for individuals aged less than 5 years, a factor ~107 (~23) for those aged 5–14 years, a factor ~28 (~10) for individuals with age in the range 15–64 years and a factor ~2.3 (~1.7) among the elderly with respect to the scenario without the adoption of any NPIs.Finally, the adoption of PPE and the practice of hand hygiene during a moderate (severe) influenza season leads to a reduction of infected and deceased individuals by a factor ~1.7 (~1.2) for individuals aged less than 4 years, a factor ~14 (~7) for those aged 5–14 years, a factor ~13 (~8) for individuals with age in the range 15–64 years, and a factor ~3.5 (~2.3) among the elderly with respect to the scenario without the adoption of any NPIs. Therefore, by considering each age class, partial lockdown is the most effective measure in containing the epidemic, especially for individuals aged less than 64 years. By contrast, PPE and hand practice hygiene are the most effective NPIs for elderly individuals for all the cases of season severity.By considering the total population regardless of age classes, our results show that the adoption of PPE and the practice of hand hygiene are the most effective NPIs in terms of reduction of infection and death during moderate influenza seasons in absence of vaccination, producing a reduction of infected (deceased) individuals by ~79% (~71%) with respect to the scenario without the adoption of NPIs and vaccination. By contrast, school closures lead to a reduction of ~22% (~3.5%) of infected (deceased) cases.However, as mentioned in Sect. 3.1, the impact of vaccination with a standard coverage leads to a reduction of ~87% (~95%) of the total fraction of infected (deceased) individuals with respect to the scenario without any vaccination and NPI. The reduction of the spread of the disease is therefore larger in the case a standard vaccination coverage is achieved with respect to the scenario where vaccination is not undertaken and with the adoption of NPIs, regardless of the nature of the NPI. An enhancement of the vaccination coverage further reduces the spread of the disease by limiting the cases of infected (deceased) individuals up to ~98% (~97%) with respect to the number of infected individuals in cases where vaccination campaigns are not undertaken. Therefore, in case of moderate influenza season, vaccination campaigns with, at least, a standard coverage make the adoption of NPIs unnecessary.However, in both cases of influenza severity, a further reduction of infected (deceased) individuals up to 99% (~100%) is obtained when standard vaccination is combined with the adoption of NPIs, regardless of which kind of NPI is adopted.In the case of severe influenza seasons and no vaccination, PPE and the practice of hand hygiene are still the most effective NPIs in terms of reduction of the total fraction of infected and deceased individuals, similarly to the case of moderate influenza season. In detail, the adoption of PPE and the practice of hand hygiene produce a reduction of infected (deceased) individuals by ~65% (~41%), while partial lockdown leads to a reduction up to ~63% (~21%) with respect to the scenario without the adoption of NPIs. These results confirm that PPE and hand hygiene are valuable measures to reduce the spread of the disease without requiring any mass intervention such as lockdown.As mentioned in Sect. 3.1 a standard vaccination coverage in severe influenza season leads to a reduction of infected (deceased) individuals by ~47% (~69%), while the enhanced vaccination produces a decrease of infected (deceased) individuals by ~92% (~84%). Therefore, in case of severe influenza season, the enhancement of the vaccination coverage is necessary to avoid the adoption of NPIs. Finally, by combining standard (enhanced) vaccination with the adoption of NPIs, we observe a further reduction of epidemic in the range between ~ 77% (~95%) and ~ 99% (~99%) for infected individuals and in the range between ~ 85% (~90%) and ~100% (~100%) for deceased individuals, regardless of the nature of the adopted NPI.The main aim of this paper is to attempt to answer the question of how currently adopted public health strategies are effective against the variety of expected scenarios of influenza in the upcoming season 2021/22. The exploration of these scenarios is needed in order to evaluate a more mindful adoption of NPIs and, possibly, a revision of currently adopted vaccination campaigns in order to prevent the spread of the epidemic by implementing appropriate vaccination campaigns and social interventions.To this aim, we have developed an age-structured SEIR model that includes the modelling of prevention and control measures, as well as the effect of social mixing patterns and the time evolution ofvaccine effectiveness in the epidemic dynamics. We present a thorough incidence analysis for three different scenarios of seasonal influenza severity under a number of hypothetical government intervention strategies (i.e. vaccination and NPIs). Based on the results of this study, vaccination campaigns with a standard coverage would produce a remarkable impact on the spread of the disease in the case of a moderate influenza season, making the adoption of NPIs unnecessary. On the contrary, NPIs are necessary in case of severe seasonal epidemics, where a standard vaccination coverage would not be sufficiently effective in fighting the disease. In this case, the combination of a vaccination with standard coverage and NPIs would lead to a significant containment of the disease. However, our results show that the enhancement of the vaccination coverage would reduce the need to adopt NPIs, thus limiting the economic and social impacts that NPIs might produce. Encompassing all the epidemic outcomes explored in this paper, it can be concluded that while the explored NPIs are effective in reducing the transmissions and mitigating the healthcare burden, it is clear that a vaccination campaign with a proper coverage is the only way to contain the epidemic.This approach suffers from some uncertainties that might affect our result. Firstly, the model assumes a population with no migration, births or deaths from causes other than the epidemic and assumes immunity to the disease upon recovery. Concerning the social mixing, the model is based on the setting-specific social interaction matrices provided by  which arHowever, this approach might be simplistic since it does not take into account the adherence of individuals to such restrictions. By accessing data related to contact tracing for confirmed cases and by carrying out large scale public surveys, the social mixing model adopted in this paper can be improved. Moreover, the model does not consider the stochastic factors, which can strongly influence the dynamics of the epidemic in the early and final stages, when there are a few numbers of infected individuals .


The use of the amphiphilic silica derivatives associated in an oligomeric medium (ASiPs) leads to structuring of the MBC due to the transetherification reaction of the terminal silanol groups of the MBC with ASiPs. It was established that the supramolecular structure of an MBC is built according to the “core-shell” structure. The obtained polymers were tested as sorbents for the development of new methods for the concentration and determination of inorganic compounds. The efficiency of sorption of reagents increased with an increase in the “thickness” of the polydimethylsiloxane component of the “shell” and with a decrease in the size of the polyisocyanurate “core”. The use of the obtained polymers as adsorbents of organic reagents is promising for increasing the efficiency of field methods of chemical testing and inorganic analysis, including the determination of the elemental composition and the detection of traces of contamination.New crosslinked (polydimethylsiloxane-ethylene-propylene oxide)-polyisocyanurate multiblock copolymers (MBCs) were synthesized, and their supramolecular structure and sorption characteristics were studied. It was found that the interaction of PPEG and D Block copolymers (BCs), including multiblock copolymers (MBCs) of amphiphilic nature, are currently attracting the efforts of researchers due to their ability to form various supramolecular structures. Block copolymers are a group of materials in which blocks from different polymer chains are chemically bonded. In most cases, the blocks are thermodynamically incompatible, but the covalent bonds between them lead to interactions, creating certain morphologies both in bulk and in solution. This behavior is a consequence of microphase separation caused by the thermodynamic incompatibility of the blocks ,9,10,11.The formation of self-assembled morphologies can be controlled by the composition of the block copolymer and the total chain length. For thin films of a block copolymer, additional interactions with a possible substrate and free interfaces should also be taken into account , whereasBlock copolymers with precisely controlled molecular weight and narrow polydispersity, consisting of two or more chemically different and incompatible segments covalently bonded to each other, attract considerable attention due to their amazing ability to separate into many nanostructures in bulk and in solution ,16,17,18In this series, polyorganosiloxane block copolymers should be discussed separately. The unique properties of polyorganosiloxanes   with an oxygen atom on the surface, or one of several forms of silanol groups (≡Si-OH). An optical chemical sensor of sulfur dioxide based on films of functional polymers for monitoring the air in the working area was considered in ,49. In ,51, nanoOver the past three decades, the development of optical sensors continued. This is primarily due to their selectivity of the ions, which is due to the incorporation of highly selective ionophores into the membrane ,53. In a4) to triblock copolymers of propylene and ethylene oxides (PPEG). A directed influence on the supramolecular organization of BC is a way to control both the physico-mechanical and physico-chemical properties of polymeric materials obtained on their basis. Promising for controlling both macromolecular and supramolecular structures are polymers based on 2,4-toluylene diisocyanate (TDI) and multiblock copolymers (MBCs) with polyorganosiloxane segments obtained by polyaddition of octamethylcyclotetrasiloxane , which have a high sorption capacity.To study the sorption capacity of the synthesized polymers, the La(III) complexes with arsenazo III were selected. The complex formation of the La(III) complexes with arsenazo III in solution has been well studied, which allows us to compare the obtained results of solid-phase sorption. However, the availability of reliable systems for the out-of-lab determination of the La(III) is limited.2CH2O]n[CH2(CH3)CH2O]m[CH2CH2O]nK where n ≈ 14 and m ≈ 51, had a molecular weight of 4200 g/mol and contained 30 wt% of peripheral polyoxyethylene blocks, where the content of potassium-alcoholate groups was 10.9% from the total number of functional groups, and was purchased from PJSC Nizhnekamskneftekhim . Octamethylcyclotetrasiloxane (D4) was purchased from Nanjing Union Silicon Chemical Co., Ltd. . Amphiphilic branched silica derivatives associated with oligomeric medium (ASiPs) were obtained in the laboratory conditions :[PPEG] = 0, 5, 10, 15. ASiPs were used as a modifier. The calculated amount of PPEG and D4, as well as ASiPs as a modifier, was placed in a round-bottom flask equipped with a reflux condenser and stirred for thirty minutes at T = 60 °C. Before conducting studies, MBCs were preheated under a residual pressure of 0.7 kPa until they reached a constant weight.The reaction was carried out in two stages. In the first stage, multiblock copolymers (MBCs) were obtained through the interaction of PPEG with D4]:[TDI]. IMBCs were also prepared on the basis of PPEG and TDI in their molar ratios, [PPEG]:[TDI] = 1:8, 1:10. The reaction was carried out in toluene at 70 °C in a flask equipped with a reflux condenser. The polymerization process was carried out with constant stirring using a magnetic stirrer. The reaction mass was stirred at this temperature until complete dissolution of the PPEG or MBCs, and then introduced TDI. Five minutes after this, the polymer-forming system was poured into a Petri dish, and then it was cured at room temperature for 72 h.In the second stage, the IMBCs were obtained by the interaction of MBCs with TDI in various molar ratios, [PPEG]::[PPEG] = 5, 10, and 15 is confirmed by 1H NMR spectra (The formation of polydimethylsiloxane segments in the MBCs obtained at [D spectra .n) in the MBC composition was calculated using the ratio of integral intensities of proton signals related to methyl groups of the propylene oxide block of PPEG  and methyl groups of the polydimethylsiloxane block  in the studied multiblock copolymer samples. The calculations were carried out using information on the content of the polypropylene oxide block (70%) and the molecular weight (4200 Da) of the commercially available PPEG. Conversion of D4 was determined as a ratio of calculated and experimental ratios of D4 and PPEG (The number of octamethyltetrasiloxane units (and PPEG .n) in the MBC composition and the conversion of D4 as a ratio of the calculated and experimental ratios of D4 and PPEG were calculated  and the molar ratio [D4]:[PPEG] at which these values were achieved allows for the conclusion that almost all PEG macromolecules participate in the polyaddition of D4.From the ratio of the proton signals corresponding to the methyl group at the silicon atom (e) and the methyl group belonging to the polyoxypropylene units (d), the number of octamethyltetrasiloxane units , the density of the nodes of the IMBC polymer framework due to the polyisocyanurates formed here is so high that an increase in the molar excess of D4 does not lead to a change in the stress–strain tests . According to 4]:[TDI] = 1:15:8 and using [ASiP] = 0.2 wt%, void disappearance is observed, but globular morphology of the IMBC surface is preserved  are able to react with detectable metal ions and form colored complexes. Currently, similar complexation reactions with immobilized ORs on other matrices are quite well studied ,61,62. C3) were used as analytes. In an aqueous solution at pH = 3÷3.8, the maximum wavelength of the complex La(III) with arsenazo III was 650 nm.In this paper, arsenazo III (AS III)  was usedFor the purpose of comparative analysis, electronic spectra were obtained a and cal4]:[TDI] = 1:15:8 was used. Similar IMBCs obtained in the presence of 0.2 wt% ASiP were also used. AS III was firstly sorbed on an IMBC from an alcohol solution. Then, film samples were sorbed from an aqueous solution of La(III). Absorption spectra of complexes La(III) with AS III formed on a polymer substrate are shown in As a polymer matrix for sorption of AS III and subsequent qualitative and quantitative determination of La(III) ions, the IMBC obtained at [PPEG]:[TDI] = 1:8, [PPEG]::[TDI] = 1:15:8 in the presence of [ASiP] = 0.2 wt% showed the highest sorption capacity compared to other test samples (4) showed significantly lower sorption capacity compared to IBMCs. The calibration curves were linear for the entire study range of La(III) ion concentrations.According to the results, the IMBC of the composition [PPEG]:[D samples . The polThus, an advantage of using IMBCs as a substrate for analysis is the ability to determine, even in a neutral environment, very low, practically trace amounts of La(III) ions.4, and TDI were investigated. It was shown that during the interaction of PPEG and D4, the polyaddition of D4 initiated by potassium-alcoholate groups occurs. It was found that an increase in the relative content of D4 leads to an increase in the size of the polydimethylsiloxane block in the MBC composition. The use of ASiPs leads to the structuring of MBCs by a transetherification reaction involving terminal silanol groups of MBCs and ASiPs. The molar ratio of PPEG, D4, and TDI was established, in which the supramolecular structure of the IMBC is formed by the “core-shell” type. Modification of IMBCs using ASiPs has a marked effect on their supramolecular structure. As a result of the transetherification reaction involving terminal silanol groups of MBCs and ASiPs, the polydimethylsiloxane component fills the free space between globular formations.Multiblock copolymers prepared using PPEG, D3. The color reaction on the IMBC polymer sorbent is reproducible, the formed polymer complex is stable for a long time, and test systems are easily applicable when working in the field. The observed higher efficiency of determination of La(III) ions with immobilized AS III is due to the fact that concentration of metal ions occurs in the IMBC matrix.The features of the supramolecular organization of IMBCs affect their sorption capacity. It was found that the sorption efficiency of organic reagents increases with an increase in the content of polydimethylsiloxane segments in the composition of the studied polymers and a decrease in the proportion of polyisocyanurates. IMBCs were investigated as a template for immobilization of the analytical organic reagent AS III used in the express and test methods. The linearity range of calibration curves when determining La(III) ions with immobilized AS III on IMBCs of any proposed composition is 5 orders of magnitude of the concentration determined in g/dm


Two kinds of CrSi2 powder were used: one was commercial powder, and the other was self-synthesized CrSi2 via mechanical alloying by planetary ball milling. The results revealed that CrSi2 particles with a larger size penetrate the melt better. Particles of three kinds were found to exist in the Al melt after the addition of CrSi2 powder: (1) inclusions of eutectic origin formed at the last stage of crystallization, (2) mixtures of Al-Cr compounds and original CrSi2 particles and (3) original CrSi2 particles. Low melt temperatures and short treatment times were found to favor the fabrication of master alloys because they impeded the dissolution of CrSi2 particles into the Al melt and, thus, allowed one to fabricate the master alloy containing the particles of the second and third types.Aluminum contaminations, particularly iron, present a serious challenge to aluminum recycling technology. This is why many studies have focused on the reduction of detrimental effects of iron-containing contaminations through addition of elements such as manganese and chromium. However, the desirable modifying effect is often difficult to achieve because it would require concentrations of added elements greater than the allowable limits for many aluminum alloys. Thus, an alternative way to obtain the modifying effect, by using a much smaller amount of the modifying elements which are added to the aluminum melt as solid particles, was proposed in this study. The main goal of the present study was to investigate the possibilities of fabricating an aluminum master alloy by adding CrSi Al-Si-casting alloys are widely used for engineering applications, especially in the automotive industry, due to their high strength, lightweight and excellent castability. Faced with the increasing demands for energy saving, aluminum manufacturers are looking for more sustainable technological routes, particularly using more secondary aluminum for alloy production. However, this inevitably results in product quality loss due to contamination, especially by iron. That is why many efforts have been made recently to develop economically acceptable technology for the reduction of the detrimental effects of iron contamination. It is well known that the addition of some transition metals to Al-Si casting alloys has a beneficial effect on the morphology of Al-Fe-Si compounds. Particularly, the addition of elements such as manganese and chromium promotes the formation of α-AlFeSi compounds with Chinese script morphology. As a result, the formation of detrimental β-AlFeSi compounds can be suppressed, at least partly. This technique has been widely used over a variety of casting alloys, and its efficiency is especially apparent in high concentrations of iron when primary intermetallic compounds are formed. For example, Bjurenstedt et.al  used a c2 particles. This mechanism is especially useful when the substrate substance is a thermodynamically stable compound, while the nucleation phase is an elementary substance or an alloy of simple composition, such as the above-mentioned TiB2 and Al, respectively. Intermetallic compounds, however, in many cases, have complicated chemical and phase compositions, varying depending on solidification conditions, particularly on the melt cooling rate. That is why it is extremely difficult, if not impossible, to discover an appropriate refiner and realize the above-mentioned nucleation mechanism for intermetallic compounds. Nevertheless, some similar nucleation-based approaches are being applied to modify some AlFeSi intermetallic compounds. The idea is that many transition elements can form binary and more complex intermetallic compounds in the aluminum melt and, thus, provide sites for the heterogeneous nucleation of AlFeSi compounds. However, the concentration of such transient elements in the alloys should be significant in order to achieve the desirable modifying effect. This is because the heterogeneous nuclei must be formed first at higher temperatures. For example, Dietrich et al.  and [Si]0 are the wt.% of Si in the ingot after and before experiments.Next, the incorporation efficiency of each powder by aluminum melt was investigated. The incorporation efficiency was defined as a weight fraction of CrSi2 particles cannot enter the melt because of the interfacial resistance. Second, some CrSi2 particles can sinter after adding onto the vortex surface. Obviously, the long time during which the particles stay close together in the vortex and in high temperatures should promote strong interactions between them that can result in their sintering. Because the density of CrSi2 is much higher than that of aluminum, such sintered lumps can enter the melt and sink down, being neither dispersed nor dissolved in it. The third reason was that part of the particles sticks to the impeller shaft during the treatment. Based on the results of 2 particles becomes faster. This can result in the formation of an intermediate layer at the interface between the aluminum melt and CrSi2 particles that should improve its wettability and incorporation efficiency.2 particles in the melt after their incorporation. Typical data of microstructural observations are presented in the figures below, and it should be mentioned that both the particles of A and B types were used, but, following 2 particles. This suggested that these fine particles have been formed as a result of the dissolution of CrSi2 in the aluminum melt, followed by the formation of new Al-Si-Fe-Cr compounds during the melt solidification.The microstructure of master alloys provides insight into the behavior of CrSi2 particles and Al-Cr intermetallic compounds. 2 particles formed aggregates in the melt. XRD analysis revealed that these large particles were composed mainly of the Al45Cr7 phase. A typical XRD pattern is shown in 2 particles in which Al was dissolved. The other areas were depleted of Si, which shows its preferential dissolution in Al according to Equation (2), as mentioned above. The remaining Cr reacted with Al, producing an Al-Cr compound. This part of particle is colored gray in the SEM view of 45Cr7.The second type of particles is relatively large intermetallic compounds composed of the primary CrSi2 particles remaining in Al. It is to be noted that such particles were only found at relatively low temperatures of the melt and short agitation time. For example, the structure shown in Finally, the third type of particles were rounded and very small particles. 2 particles was extremely low. Therefore, iron could only enter the particles from aluminum which contained about 0.06% of Fe as an impurity. It was assumed that this phenomenon occurred when the melts were cooled down.Further SEM investigations of such particles showed interesting details regarding their chemical composition and formation mechanism. 2 particles that have smaller sizes than purchased CrSi2 particles. In addition, the agglomeration of fine CrSi2 particles during 15 h of the ball milling process was assumed to be responsible for the appearance of coarse particles as large as 100 μm. Similar results were obtained by other research groups. For example, Kumar et al. [The ball milling time had a major effect on the particle size distribution. Comparing with r et al.  investig2 has reacted with Al, for example, according to Equation (1), to form a well-wetted layer on the surface of CrSi2 particles.Particles size has a great influence on the incorporation efficiency. The results of our previous research revealed that larger particles have a higher incorporation efficiency, which can be explained according to the following two mechanisms : The fir2 particles into the Al melt. In this section, the corresponding formation mechanisms were discussed. Firstly, the dissolution mechanism of added CrSi2 particles into the Al melt were discussed to clarify the key parameters influencing the dissolution time of CrSi2 particles.As shown in the result part, three typical compounds were formed after adding the CrSi2 compounds can dissolve significant amounts of aluminum. Therefore, the particle dissolution into the melt and the mass transfer of Al from the melt into the particle may proceed simultaneously. Obviously, both these phenomena are controlled by diffusion and should be taken into account. However, because the diffusion coefficients in liquids and solids may differ by two or more orders of magnitude, the dissolution of Al in solid CrSi2 particles was neglected in the present analysis. Below is a simplified model of the dissolution of a single CrSi2 particle. The model was derived under the following assumptions:The particle is spherical in shape;Dissolution is controlled by the mass transfer of chromium in molten aluminum;The concentration of chromium at the solid–liquid interface is equal to its solubility limit in aluminum at a given temperature.2 particle and the aluminum melt, As mentioned in the introduction section, CrSik, one can derive the following equation:From the insertion of the appropriate expressions for r is the particle radius and In Equation (4), tion (5) :(5)DCr=2k, in Equation (4) was calculated from the Ranz and Marshall correlation for a sphere according to the following equations:Sh, Re and Sc are the Sherwood, Reynolds and Schmidt numbers, respectively; d is the particle diameter; pu is the sedimentation velocity of particles in the melt; and ν is the kinematic viscosity of the melt. It can be shown that the second term of this equation is much smaller than 2.0. Below is a calculation example for CrSi2 particles that have two typical diameters, 2 μm and 20 μm.Notice that the mass transfer coefficient, g is the gravity acceleration and μ is the dynamic viscosity of the melt. The calculations were performed using the following data: 3, 3, and pu = 4.9 × 10−6 m/s and 4.9 × 10−4 m/s for particle diameters of 2 μm and 20 μm, respectively. The insertion of these values into Equation (8) gave Re = 1.95 × 10−5 and 1.95 × 10−2 for the particles of 2 μm and 20 μm, respectively. The Schmidt number was calculated to be 94.3 for the above physical properties. Then, one could calculate the second term of the right part of Equation (6), which describes the convective mass transfer. The results gave 0.012 and 0.38 for the particle diameters of 2 and 20 μm, respectively. Therefore, in the case of fine particles with the size of a few microns, the convective mass transfer was negligibly small. For the particles of a few tens of microns in diameter, although the contribution of the convective mass transfer became larger, it was still significantly smaller than that of diffusion and was ignored in the derivation of Equation (4). After integration of Equation (4), one arrived at an Equation (11), describing the time, dt, required for the complete dissolution of CrSi2 particles in the aluminum melt.For fine particles, the sedimentation velocity can be determined from the Stokes law asCrC in Equation (4) is much smaller than Cr,eC, the former was ignored in deriving Equation (11). The calculation by this equation revealed that the dissolution time was very short. For example, the dissolution time of a 20 μm particle was about 11 s at the melt temperature of 750 °C.Notice that, since 2 particles, which could significantly impede the dissolution rate. For example, as seen in 2 particles initially formed agglomerates. These particles were observable in these figures as small white spots. 2 particles were embedded into the Al-Cr matrix. Obviously, the Al-Cr compounds are formed when the melt temperature decreases. Therefore, a slight reduction in the melt temperature during the penetration of CrSi2 particles in the melt is a desirable condition to enhance the formation of the Al-Cr layer on the particle surface and, thus, to suppress particle dissolution. Another problem to be solved is the suppression of the agglomeration of particles. One possible solution for this is to apply ultrasound vibrations to the melt containing the particle agglomerates. These issues will be the subject of our future investigation.However, as mentioned above, this model did not take into account the possible formation of a solid layer on the original CrSi2 particles, they may contain significant amounts of Al dissolving into the particles according to the mechanism discussed above. After completing the melt stirring, it was poured into a steel mold. During the cooling down process, some amount of Fe, which exists in the melt as an impurity, could dissolve into the particles to eventually produce nuclei of Al-Cr-Fe-Si compounds. Although the system as a whole may be far from equilibrium, an appropriate phase diagram could be helpful in understanding in which direction the system must change to reach equilibrium locally. One more important point to be mentioned was the detection of Fe inside the small particles shown in 2 particles had time to dissolve in the melt, and then, when the melt was cooled down, Al9Fe2Si2 and Al13Cr4Si4 compounds coexisted with liquid and solid aluminum within a narrow temperature range, as shown in 2 particles in small amounts, as shown in When the melt temperature during mechanical stirring was high and its duration was long, CrSi2 particles into molten aluminum was investigated. The master alloys were designed to use it for the modification of Fe-containing intermetallic compounds in aluminum alloys with a higher concentration of iron. CrSi2 particles were synthesized by ball milling and then added onto the surface of a vortex formed during the mechanical agitation of an aluminum melt. Factors influencing the particle synthesis performance, the incorporation efficiency into the melt and the morphology of intermetallic compounds in the fabricated master alloys were considered, with the main emphasis being placed on dissolution mechanisms when CrSi2 particles entered the Al melt. Based on the above results and discussion, the following conclusions can be drawn from this study:In the present work, the fabrication process of master alloys by adding CrSi2 particles, and 15 h of ball milling is enough for original Cr and Si powders to be completely turned into CrSi2. When compared to commercial CrSi2 powder, the self-synthesized one has a broader size distribution of particles, with the largest ones, up to 100 μm, formed because of agglomeration.1. Ball milling is an effective way to produce CrSi2 particle size has a great influence on the incorporation efficiency. Specifically, larger particles penetrate the melt better. This is assumed to be due to a combined effect of capillary and inertial forces acting on particles adhered to the melt surface in the vortex.2. CrSi2 particles rapidly dissolve in the melt. This suggested that the fast formation of a layer of Al-Cr compounds on the surface of CrSi2 particles is of prime importance for the master alloy fabrication.3. The low temperature of the melt and the shorter time of mechanical stirring are desirable for the master alloy fabrication because of the suppression of the particle dissolution under these conditions. Nevertheless, the results of theoretical consideration revealed that, even at lower temperatures, the CrSi2 particles: (1) inclusions of eutectic origin formed at the last stage of crystallization, (2) mixtures of Al-Cr compounds and original CrSi2 particles and (3) original CrSi2 particles. Furthermore, low melt temperatures and short treatment times were found to favor the fabrication of master alloys because they prevent the dissolution of CrSi2 particles into Al melts, which allows one to fabricate the master alloy containing the particles of the second and third types.4. There are at least three types of intermetallic compounds that were found to exist in the Al melt after addition of CrSi2 particles would be favorable to accelerate the formation of the Al-Cr layer on the particle surface and to break the particle agglomerates. These issues will be the subjects of our future works.5. The above results suggested that a slight reduction in the melt temperature and the introduction of ultrasound vibrations in the melt after addition of CrSi