With the widespread application of circulating fluidized bed (CFB) combustion technology, the popularity of CFB ash (CFBA) has increased dramatically and its production and large-scale utilization have become increasingly important. In the context of carbon neutrality peaking, using CFBA as a cement admixture as an effective method of resource utilization not only reduces the pressures caused by carbon emissions in the cement industry but also solves the environmental problems caused by CFBA depositing. However, the formation conditions of CFBA are worse than those of traditional pulverized coal boilers. CFB ash is the combustion product of coal at 850 °C–950 °C, and the characteristics of CFBA usually include a loose and porous structure with many amorphous substances. Furthermore, it has the disadvantages of large particle size, high water-demand ratio, and low activity index when it is directly used as a cement admixture. In this study, CFBA (including fly ash (CFBFA) and bottom ash (CFBBA)) produced by a CFB boiler without furnace desulfurization with limestone was used as a cement admixture material, and the effect of grinding on the fineness, water-demand ratio, and activity index of CFBA were studied. The experimental results showed that the grinding effect could significantly reduce the fineness and water-demand ratio of CFBA as a cement mixture and improve the activity index. With the increase in the grinding time, the water-demand ratio of CFBA first decreased and then increased. CFBBA ground for 10 min and CFBFA ground for 4 min can reduce the water-demand ratio of CFBA by up to 105% and increase the compressive strength of 28-day-old CFBA cement by 7.05%. The grinding process can ensure that CFBA meets the Chinese standards for a cement admixture and realize the resource utilization of CFBA. Circulating fluidized bed (CFB) combustion technology is widely used because of its good fuel flexibility, low pollution emissions, and large turndown ratio ,2,3. A lCFB combustion technology was developed after pulverized coal (PC) boilers so the research on ash utilization is lagging. CFB ash utilization has been studied in the literature in recent years including its use as a fine aggregate in compacted concrete , as a ge2 emission. The CaO decomposed by the limestone in the boiler reacts with SO2, thus reducing the SO2 content in the gas emission and ensuring that the SO2 concentration in the exhaust gas meets the national requirements, which is of great significance to the control of pollutants [However, CFB ash is the combustion product of coal at 850 °C–950 °C , and thellutants ,26. Thisllutants ,28,29.Wu et al. stated that CFBC fly ash has the potential to replace cementitious materials and is a substitute for pozzolan . Li et aTkaczewska, E. used different admixtures of sulfonated melamine-formaldehyde condensate, sulfonated naphthalene-formaldehyde condensate, polycarboxylate, and polycarboxylate ether, resulting in a 15%, 31%, 42%, and 47% reduction in the water-demand ratio of fly ash .Zheng et al. conducted a study under the condition of a water/cement (W/C) ratio of 0.35 and an amount of polycarboxylate superplasticizer of 0.2% by weight of cementitious materials was added to the mixture. The water-demand ratio was effectively reduced but the mortar intensity also decreased .Sun et al. considered the strength, expansion, and void ratio for optimizing the ratio of the CFB ash–anhydrite–clinker so that CFB ash could be used as the source of the aluminosilicate material for supersulfated cement, thereby reducing carbon emissions .3 and free CaO, which limits its application. Even if power plants adopt flue gas desulfurization technology outside the boiler to reduce the content of sulfur and free CaO in CFBA, there are still problems such as a large particle size, large water-demand ratio, and low activity index when CFBA is directly used as a cement admixture. Grinding can reduce the problems of the particle size and water-demand ratio of CFBA [CFBA contains more SO of CFBA ,33,34,35In this study, the focus is on the problems of the large particle size, large water-demand ratio, and low activity index of the CFBA produced by a 300 MW CFB boiler with external flue gas desulfurization technology in order to ensure that CFBA meets the Chinese standards for its use as a cement admixture. Furthermore, the effects of grinding on the fineness, water-demand ratio, and activity index of CFBA were studied, and the results provide new ideas for carbon reduction and CFB ash utilization in the cement industry.The CFBA used in the test was from the 300 MW CFB boiler of Guotou Panjiang Power Co., Ltd.  and included CFB fly ash (CFBFA) and CFB bottom ash (CFBBA). The cement was PI42.5 Portland cement and was sourced from China Fushun Cement Co., Ltd.  Standard sand was standard sand produced by Xiamen ISO Standard Sand Co., Ltd. . The water was deionized.3 mass fraction, free CaO mass fraction, SiO2, Al2O3 and Fe2O3 total mass fraction, density, water-demand ratio, and strength activity index. Each experiment was measured at least twice and for some important research data (water-demand ratio and mild activity index), each experiment was measured at least three times.In order to ensure that CFBA meets the requirements of cement admixtures found in Chinese standard GB-T 1596-2017, the required tests of CFBA in this study included fineness, loss of ignition, water content, total SOThe experimental process is shown in An XQM-4 vertical planetary mill produced by Changsha Tianchuang Powder Technology Co., Ltd.  was used for grinding. The CFBFA and CFBBA were ground separately. The mass of the ash sample was 100 g per grinding, the speed of the ball mill was 300 r/min, and the variable condition was the grinding time. After the grinding, the ash sample was sieved through a sieve with a pore diameter of 0.9 mm, and the ash sample under the sieve was tested and used as a cement mixing material.The SEM detection of CFBA was carried out with a Merlin Compact type Scanning Electron Microscope produced by Carl Zeiss AG  under the conditions of an accelerating voltage of 0.05–30 kV and a resolution of 1.0 nm/15 kV.The particle size and specific surface area of CFBA were measured under SOP using a Mastersizer 2000 laser particle sizer produced by Malvern Instruments Ltd. . The compound composition of CFBA was detected using an ARL PERFORM X-ray fluorescence spectrometer produced by Thermo Fisher . The operating technical indicators were target material: Rh; light tube power: 4 KW; excitation voltage: 60 kV (max); and excitation current: 140 mA (max). Equipped with 9 dichroic crystals, the element test range was B-U. The density of CFBA was measured according to Archimedes’ principle using Lee’s bottles and kerosene. Its value is the ratio of the weight of the ash residue to the increased volume of kerosene. The fineness of CFBA refers to the percentage of total mass on the screen after the CFBA was screened using an FYS-150B cement fineness negative pressure sieve analyzer (sieve hole is 45 μm) produced by Hebei Xinglan Construction Instrument Co., Ltd. .The loss of ignition (LOI) of CFBA was detected using an AS-1700 muffle furnace produced by Zhengzhou Ansheng Scientific Instrument Co., Ltd. . The method involved placing the CFBA into the muffle furnace, gradually increasing the temperature starting at room temperature, burning at 950 ± 25 °C for 1 h, and then placing the CFBA into the desiccator to cool it down to room temperature; the percentage of the mass CFBA lost to the total mass is the LOI.The method for determining the water-demand ratio of CFBA was as follows. After the contrasting mortar and test mortar were stirred evenly under certain conditions according to the material ratio shown in The CFBA intensity activity index was measured as follows. First, according to the composition shown in 2 and CaO contents in boiler CFBFA and high Fe2O3 content in CFBBA. There are a lot of active SiO2 and Al2O3 contents in CFBA [2 generated in cement to generate gel products such as CaO–SiO2–H2O, CaO–Al2O3–H2O, etc. These gel products provide strength for the mortar. Flue gas desulfurization technology is used outside the boiler and the limestone is not placed into the furnace during the boiler operation so the contents of CaO and SO3 in CFBA are lower than those in traditional CFBA and free CaO is rarely almost negligible. This is more beneficial to the use of CFBA as a cement admixture. in CFBA , which hStudies have shown that CFBA needs to meet the requirements of second-class pulverized coal ash for use in a cement admixture according to standard GB-T 1596-2017. The fineness, water-demand ratio, LOI, moisture content, sulfur trioxide, density, and activity index of CFBFA and CFBBA were measured, respectively, during the experiment. As listed in The results of the fineness of CFBBA after different grinding times are shown in The SEM images of CFBBA after different grinding times are shown in The main reason for the above results is that there were fracture intersections of lattice destruction in the fine particles, which made the surface of the fine particles have a large number of electric charges and the particles were attracted to each other by electrostatic force and van der Waals force resulting in agglomeration. The particles’ agglomeration caused the large particles to be wrapped in the fine particles. When the steel balls ground the particles, the force between the particles had to be overcome to continue grinding, which not only reduced the grinding efficiency but also increased the grinding energy consumption.In the actual operation of the CFB boiler, the mass ratio of CFBFA and CFBBA is 7:3. In order to realize the full utilization of CFBA, in the experiment on the water-demand ratio, CFBFA and CFBBA were ground and mixed into cement according to this ratio to measure the water-demand ratio. The water-demand ratio method was introduced in Because the fineness of CFBFA can meet the requirements of standard GB/T 1596-2017 even without grinding, only CFBBA needed to be ground. The water-demand ratio of CFBA with grinding time is shown in Many factors affect the water-demand ratio of CFBA including the chemical composition, carbon content, particle size, and particle shape of CFBA. The chemical composition of CFBA in this experiment was fixed so its mechanism can be explained by three other aspects. In (a)As shown in (b)As shown in (c)The effect of the carbon content of CFBA on the water-demand ratio was also tested. Wu Bin et al. showed that the water-demand ratio of pulverized coal ash increased with the increase in the carbon content . SimilarFor the first test, with the increase in the CFBBA grinding time, the water-demand ratio of CFBA first decreased and then increased because (a) and (b) played a major role. The reason that the minimum value could reach 105% was that only CFBBA was ground, whereas CFBFA was not, and the carbon content of CFBA is high. So, a second experiment was needed.In the second experiment, the grinding time of CFBBA was fixed at 10 min, and then CFBFA was ground at different times. The results of the water-demand ratio of CFBA are shown in In this experiment based on a mixing ratio of CFBFA to CFBBA of 7:3, considering the cost of grinding, “the grinding time of CFBFA is 4 min, and the grinding time of CFBBA is 10 min” were the best grinding times for meeting the water-demand ratio of the CFBA conditions.2 and Al2O3 in CFBA to have a larger contact area to react with the cement, which sped up the reaction rate and improved the compressive and flexural strengths of the mortar. When the grinding time of CFBBA reached a certain condition, the reaction rate did not increase after reaching the maximum. Therefore, grinding for a certain period of time can promote the strength of CFBA cement admixture mortar, which is consistent with the conclusions of previous experiments [The compressive and flexural strengths of the CFBA mortar were tested according to the GB/T 1596-2017 standard. Similar to the test for the water-demand ratio, CFBFA: CFBBA was mixed into the cement at a ratio of 7:3 to test the compressive and flexural strengths of the mortar. The experimental method was described in eriments .The relationship between the strength activity indexes of CFBA at 3 d, 7 d, and 28 d with the grinding times of CFBBA is shown in 2 and Al2O3 in CFBA were even higher, and the sulfur and free CaO were lower. Because three parameters did not meet the standards, the grinding process was used to study the effect of the grinding time on the fineness and water-demand ratio of CFBA and the compressive and flexural strengths of the mortar. The results showed that the grinding process could ensure that CFBA meets the standards for second-class pulverized coal ash as a cement admixture. The main conclusions are as follows.In this study, the ash from a CFB boiler without in-furnace desulfurization used as a cement admixture was studied. Most of the physical and chemical properties of CFBA met the applicable Chinese standards of second-class pulverized coal ash, the contents of SiOGrinding can effectively reduce the particle size of CFBA and ensure it meets the standard requirements. However, with the increase in grinding time, the particles are attracted by electrostatic force and van der Waals force, and the particle size of CFBA caused by agglomeration increases.Grinding can reduce the water-demand ratio of CFBA. Because the fineness of CFBFA is still relatively coarse and the carbon content of CFBFA is higher, grinding only CFBBA cannot ensure that CFBA meets the water-demand ratio requirement. When the grinding time of CFBBA is 10 min and the grinding time of CFBFA is 4 min, the water-demand ratio of CFB meets the requirements.Grinding can improve the compressive and flexural strengths of the mortar when CFBA is used as a cement admixture. Under the condition that the grinding time of CFBFA is 4 min, when the grinding time of CFBBA is 10 min rather than 2 min, the compressive strength of the 28-day-old mortar test block of CFBA increases by 7.05% and the flexural strength changes slightly. The strength activity coefficient of CFBA at 28 d meets the requirements of cement admixtures.CFBA can be used as a cement admixture to meet the requirements of the GB/T 1596-2017 standard by grinding. The optimal grinding time of CFBBA is 10 min and the optimal grinding time of CFBFA is 4 min.


Shortcomings of the current school-based infectious disease syndromic surveillance system (SSS) in China include relying on school physicians to collect data manually and ignoring the health information of students in attendance.This study aimed to design and implement an influenza SSS based on the absenteeism (collected by face recognition) and temperature of attending students .An SSS was implemented by extending the functionality of an existing application. The system was implemented in 2 primary schools and 1 junior high school in the Yangtze River Delta, with a total of 3535 students. The examination period was from March 1, 2021, to January 14, 2022, with 174 effective days. The daily and weekly absenteeism and fever rates reported by the system  were calculated. The daily and weekly absenteeism rates reported by school physicians (DAR2 and WAR2) and the weekly positive rate of influenza virus  were used as standards to evaluate the quality of the data reported by the system.r=0.372, P=.002). When the influenza activity level was moderate, DAR1s were significantly positively correlated among schools . During the influenza breakout, the gap of DAR1s widened. WAR1 peaked 2 weeks earlier in schools A and B than in school C. Variables significantly positively correlated with the WPRIV were the WAR1 and WAR2 of school A, WAR1 of school C, and WFR of school B. The correlation between the WAR1 and WPRIV was greater than that between the WAR2 and WPRIV in school A. Addition of the WFR to the WAR1 of school B increased the correlation between the WAR1 and WPRIV.Absenteeism reported by school physicians (completeness 86.7%) was 36.5% of that reported by this system (completeness 100%), and a significant positive correlation between them was detected (Data demonstrated that absenteeism calculation based on face recognition was reliable, but the accuracy of the temperature recorded by the infrared thermometer should be enhanced. Compared with similar SSSs, this system has superior simplicity, cost-effectiveness, data quality, sensitivity, and timeliness. School-aged children are vulnerable to influenza. The incidence of influenza among children aged 5-14 years during the influenza season ranges from 17.31% to 46.61% ,3. An inAbsenteeism is an influenza surveillance indicator recommended by the World Health Organization and an important determinant adopted in the school-based syndromic surveillance system (SSS). In 1979, Peterson et al  demonstrAbsenteeism can be divided into three types: all-cause absence, illness absence, and syndrome-specific absence . These 3Public health emergencies of infectious diseases emerging from schools account for 85.64% of the total number of all annual national public health emergencies . TherefoUsing artificial intelligence and information technology instead of manual methods to collect absenteeism data while considering the health information of students in attendance is highly important to solve the current development dilemma of SSS in China. To this end, an SSS was designed and trial-operated, which realized synchronous acquisition of identity, absenteeism, and temperature data based on face recognition and thermal imaging. The system has been in operation at 3 sentinel schools in the Yangtze River Delta region since November 2020. Data from these 3 schools collected by the system between March 2021 and January 2022 were exported to investigate 2 aspects. First, the alternative method of manually collecting absenteeism data explored in previous studies has produced a large amount of erroneous data . SimultaThe proposed SSS was based on an app called “Xiao Lian Xing” (XLX) , which cThe operating company signed service agreements with the school and its superior management organization. According to the agreement, the school organized for the parents to register an account in Alipay with a smart phone (registration was completely voluntary), and then input information about the child, such as the name, gender, ID, school name, class, and face image into the account. Parents can also use the account to check the attendance and temperature of their children. The system collected student attendance and temperature data through terminal devices, which were composed of 2 modules, namely a face recognition system  and an infrared thermometer . The 2 modules were connected using a self-designed software for synchronous input and upload of the identity, attendance, and temperature. The data processing center was responsible for processing the data uploaded by each terminal and relaying the analysis results of absenteeism and fever at different levels to family users , school users , and school district management department users.Terminal devices were generally arranged at the school gate. After students arrived at school every day, they went to the device for testing. Face recognition of the students was performed, and their identity information, attendance information, and facial temperature were automatically recorded by the instrument. Only students who were identified and had a normal temperature were admitted directly, whereas students with fever (temperature≥37.3℃) were processed separately. To ensure that every student was subjected to instrument testing, the school arranged for staff on duty to supervise the children. Daily information on student attendance and temperature was transmitted to the cloud data center in real time. The data processing center generated a daily statistical report of the check-in and body temperature (with infrared images) of students in real time , summariThe study population comprised 3 schools in the Yangtze River Delta region. Schools A and B were primary schools. School A, located in Xiaoshan District, Hangzhou city, Zhejiang Province, began to use version 1.0 of the system (only face recognition) in November 2020 and version 2.0 (face recognition and infrared thermometer) in March 2021. School B, located in Binjiang District of Hangzhou city, began to pilot version 2.0 of the system in March 2021; it allowed students to use smart cards to check-in and began to fully use version 2.0 in September 2021. School C is a junior high school located in Pudong District, Shanghai, and it started to use version 2.0 of this system in October 2021.The surveillance period was divided into 2 phases, namely, phase I, from March 1, 2021, to June 25, 2021, and phase II, from September 1, 2021, to January 14, 2022. The effective surveillance times of these phases were 83 and 91 days in total, respectively. In phase I, the numbers of students in school A and B were 1861 and 1100, respectively. In phase II, the numbers of students in schools A, B, and C were 1954, 1154, and 427, respectively, with a total of 3535 students. The system collected the following data for each school: total number of enrolled students, number of daily absentees, and number of daily students with fever. By default, students who failed to check-in within 1 hour after the specified arrival time were counted as absenteeism cases, where students whose body temperature was ≥37.3℃ were counted as fever cases.The absenteeism reported by physicians in schools A and B (school C has no record of the school physician) was collected as the reference standard to evaluate the quality of absenteeism reported by the system. Absenteeism reported by the school physicians was defined as “the student is not in school that day.” The data reported by school physicians were collected from September 1, 2021, to January 14, 2022. To verify the reliability and feasibility of the surveillance system for infectious diseases, influenza was selected as the target disease. The reference criteria for influenza activities were obtained from the weekly influenza surveillance report released by Chinese National Influenza Center . These wData used in this study were anonymized, so the Tongji University Review Board classified this study as nonhuman subject research, and it was exempted from approval.The daily absence rate (DAR) of the 3 schools was calculated as follows:The DAR is divided into two categories: system-reported (DAR1) and school physician–reported (DAR2). The correlation coefficient of the 2 variables was then calculated. According to relevant literature ,12, the Second, according to the time series diagram of DAR1 , the staThe DFR time series diagrams of the 3 schools are shown in Third, based on the DAR and DFR, the weekly absenteeism rate (WAR) and weekly fever rate (WFR) for the three schools were calculated as follows:The time series diagrams of the WAR and WFR of the 3 schools were produced, and their coincidence with the time series diagram trends of the WPRIV was compared -8.t; then the WPRIV sequence was advanced by 1 week (t– 1), 2 weeks (t–2), and 3 weeks (t–3). The correlation of the WPRIV with the aforementioned WARs and WFRs and their sum was calculated under these 4 conditions to investigate the reliability, accuracy, and timeliness of different types of data derived from this system for influenza activity surveillance.Finally, the following statistical process was performed: (1) The sums of the WAR and WFR of each school were calculated. (2) Based on the data of school A, the data of school B were added at the beginning of week 37; then the data of school C were added again in week 45, and then the combined WAR and WFR were combined based on the weight of the total enrollment in each school. (3) The sums of the combined WAR and WFR were calculated. Simultaneously, the current time was set to In phase I, all 2961 students in schools A and B had registered accounts in the system. In phase II, the total number of students in the 3 schools was 3535, with 3530 students (99.86%) having registered accounts . The DARra=0.508, P=.004), B and C , and A and C , were moderately positively correlated. After December 20, the DARs at the 3 schools showed different trends, with the differences between school C and the other 2 schools being significantly different.The DAR1s of the 3 schools were very similar along with the trends over the 30 monitoring days from November 8 to December 20 . During Between September 1, 2021, and January 14, 2022, students from school A were expected to attend school for 92 days and students from school B for 90 days. Both the system and the school physician of school A recorded 92 days of data. A total of 5128 absences were reported by the system, whereas a total of 1476 absences were reported by the school physicians, with the latter accounting for 28.78% of the former. In school B, the system recorded 3452 absences over 90 days, whereas the school physician recorded 1691 absences over 66 days (73.3% completeness), with the number reported by school physicians being 48.99% of the number reported by the system.r=0.809, P<.001), and their change trends were highly consistent. In school B, DAR1 and DAR2 were also significantly positively correlated , but there was a notable gap between them in November 2021 .A significant positive correlation between DAR1 and DAR2 in school A was detected , for school B from September 13, 2021 (week 37), and for school C from November 8, 2021 (week 45). The infrared image investigation of the system confirmed that high-temperature objects were placed next to the infrared thermometer in school A on 2 days , and on 1 day (April 1), the thermometer was unable to measure temperatures owing to physical failure. In school B, there were 2 days (November 11 and December 29) when a high-temperature object was placed next to the thermometer. The DFR of these 5 days was regarded as a missing value and replaced with the mean of the DFR for the previous and next days.rac=0.493, P<.001). Although no significant correlation was detected between schools A and B , and schools B and C , the DFR curves of the 3 schools were consistent in some wave peaks and troughs.Overall, the DFR curve of school A resembles a parabola with a downward opening . This trThe WAR1s and WFRs for the 3 schools were calculated, and their time series diagrams were plotted. The WAR1 of school A was consistent with the trend of the WPRIV , that isSchool B showed a peak of the WAR1 in weeks 42 and 43 . InvestiThe surveillance weeks of school C were few, and the WAR1 of school C has been on the rise throughout the surveillance period , which wt–3, the correlation coefficient between the WAR1 of school A and WPRIV was the highest, whereas at t, the correlation coefficient between the WAR of school C and WPRIV was the highest (t–3. The addition of the WAR1 to the WFR produced an increased correlation with the WPRIV only in the sum of school B. The WAR1 of school A reported by the school physician was significantly positively correlated with the WPRIV, with the maximum coefficient located at t–3. The correlation coefficients between the WAR1 and WPRIV that were calculated based on system-reported data were higher than those calculated based on data reported by school physicians in each condition. The WAR1 of school B reported by both the school physician and the proposed system was not significantly correlated with the WPRIV in any of the 4 conditions.Among the WAR1s reported by the system, only the WAR1 of schools A and C was significantly positively correlated with the WPRIV. At  highest . AlthougIn 2017, Groseclose and Buckeridge  proposedThis system is simple to operate and has a low construction cost. The simplicity of the proposed surveillance system is reflected in four aspects: data availability and type, organization and type, data exchange and conversion, and personnel operation and training . SicknesThe absenteeism reported by the system was complete and accurate, and the completeness of the temperature was high, but the accuracy needs to be improved. Fingerprints, smart cards, or face recognition were used to guarantee that every student in attendance is checked and accurately identified. Lawpoolsri et al  attempteThe proposed system showed good sensitivity. The surveillance sensitivity includes case detection, outbreak detection, and case definition . ExistinThe results also showed good timeliness rates. The data of this system were transmitted in real time and analyzed automatically. Parents, teachers, and administrators were able to instantly access the attendance and temperature status of an individual, class, and school. Baer et al  proposedFirst, although thermal infrared imaging is simple, its accuracy is easily influenced by environmental factors . BecauseComparison of the proposed system with existing similar systems showed its advantages in terms of simplicity, cost-effectiveness, data quality, sensitivity, and timeliness. This study showed that the absenteeism recorded using face recognition technology was reliable, but the accuracy of the temperature recorded by infrared thermometers should be enhanced. The implementation of the influenza SSS based on absenteeism and temperature data was feasible. When influenza activity levels were moderate, a significant positive correlation between the DARs was detected; however, as the levels increased, the gap among the DARs gradually increased and peaked about 2 weeks earlier in primary schools than in junior high schools. The introduction of temperature measurement substantially strengthened the surveillance timeliness, allowing detection of influenza outbreaks up to 3 weeks earlier than traditional systems. This study demonstrated a feasible way to solve the challenge of developing a surveillance system and promote the automation of symptom data acquisition in the surveillance system.


To achieve the new level of blended cement performance, the slurries of Class C and F fly ash were mechano-chemically activated in a vibro-mill with superplasticizer and nanosilica. The resulting activated products were tested in mortars replacing up to 30% portland cement. The activation process resulted in the formation of nano-seed clusters and micronized ash particles that both significantly improve the early strength of mortars as well as allow for the replacement of portland cement with industrial by-products. A small amount, 0.1% (of a binder weight), of nanosilica was used in selected compositions to improve the process of activation and facilitate the formation of nano-seeds. Due to an intensive activation of fly ash in the vibro-mill and the formation of nano-seed hydration products, the increase in the heat of the hydration flux and improvement of the mechanical properties such as compressive strength, especially in the early stages of hardening, were achieved. It is envisioned that fly ash activation and the use of supplementary cementitious materials as a precursor can induce a denser structure of cementitious matrix due to better particle packing realized with the application of the nano-seed product, nanosilica, ultra-fine particles of fly ash, and the formation of a refined C-S-H structure realized with the incorporation of the nano-seed particles. The primary trend in sustainable construction embraces the effective use of concrete with supplementary cementitious materials (SCM) and mineral admixtures, including high-performance, self-consolidating, and other types of high-end concrete ,2. In ad2 and nano-CaCO3 on the strength development of fly ash and portland cement-based mortars [The use of nanoparticles in modern concrete comprises another important trend ,13,14,15 mortars . DespiteIn addition to nanosilica and chemical activation, overcoming poor early-age strength performance through the mechanical activation of cementitious materials has also been proposed ,5,7. TheA new concept of nano-engineered cement combined with mechano-chemical activation (MCA), accelerated hydration, and the formation of nano-cement and nano C-S-H seed clusters has been previously proposed by the authors . It was The overall objective of the reported research was to evaluate the feasibility of a new eco-cement concept based on the mechano-chemical activation of fly ash-nanoparticle–superplasticizer blends using liquid-state milling and to illustrate how these processes can be tuned to facilitate the hydration, improve the early strength, and, overall, the performance of blended cement composites.The portland cement (PC) type I used in this study was supplied by Lafarge-Holcim. The chemical and physical properties of portland cement (as tested by the manufacturer) are given in The mineral composition of fly ash and the effects of activation were determined by X-ray diffraction (XRD) using the XDS 2000 instrument from Scintag , running on step-scanning mode, and reported in 2Θ units. The particle size distribution and zeta potential of activated ash materials were tested using the Dynamic Light Scattering (DLS) method with a NanoBrook ZetaPALS from Brookhaven Instruments .Two different types of colloidal nanosilica, supplied by Nouryon , were evaluated for this study. The Cembinder 50 (CB50) product is characterized by an average particle size of 5 nm and a solid concentration of 15%; Cembinder 8 (CB8) is represented by products with a larger particle size range of 10–100 nm and a solid concentration of 50%, as reported by A polycarboxylate ether (PCE) superplasticizer (SP) with 38.7% solid concentration supplied by Handy Chemicals was used as a surfactant. Graded Ottawa sand complying to ASTM C778  was usedMechanical activation is an effective method for improving the reactivity of blended cement, as the fine grinding of cementitious materials creates a greater surface area available for hydration. Preliminary research indicated the potential of MCA to significantly improve mechanical properties and to accelerate cement hydration due to the presence of nanosized and submicron phases ,23,24,25z_15 and Az_45 series of samples, where z is the activation time in hours), as described in reference [To identify the effect of mechano-activation, the Class C fly ash product used in this study was subjected to wet vibro-milling for 2 and 3 h, designated as A2 and A3 set of samples, respectively. After milling, the evaluation of the particle size distribution and zeta potential of the activated ash product were performed using diluted slurries, with the samples collected from the top 20% portion of a container after 15 and 45 min of gravitational sedimentation  NanoBrook ZetaPALS Particle Sizing Instrument was used to obtain the particle size and evaluate the polydispersity. This instrument uses the principle of dynamic light scattering (DLS). Initially, 2 mL of 18.2 MΩ water is placed into a disposable 10 mm square acrylic cuvette. A drop of activated ash suspension  was then added into the cuvette for each run, and the sample was gently mixed, resulting in a slight turbidity. The cuvette was then placed in the holder of the instrument for the analysis. All tests were conducted at 25 °C, and 10 runs were used to determine the particle size distribution, mean effective diameter, and polydispersity. The same equipment was used to obtain the z- (ζ-) potential of the suspensions. For this experiment, a small amount of activated ash suspension was dispersed in 0.1 mM KNOThe results of the DLS and zeta potential tests are depicted in This experiment proves that after 2 h of wet vibro-milling, some portion (up to 7%) of colloidal fly ash particles can be reduced to nano size (<100 nm).The mortars based on blended binders with activated ash were produced at a water to cementitious materials ratio (W/C) of 0.36 and a sand to cementitious materials ratio (S/C) of 1, as further presented in Two experimental approaches were explored to realize the proposed concept: first, mechano-chemical activation was used to activate Class F fly ash, which was used at a replacement level of 20%, and combined with an additional 10% of non-activated (plain) fly ash. Here, the activation of 20% of Class F fly ash was carried in a water solution with superplasticizer (SP), and the remaining 10% of the dry fly ash was added with the cement at the mortar-mixing stage. The SP was used at a constant dosage of 0.15% by mass of cementitious materials to facilitate the dispersion of fly ash during the liquid-state milling (when used in activated systems). The fly ash component was activated in a vibro-mill at a grinding media to powder ratio of 10:1, leading to an effective reduction of particle size and a change in particle shape, as demonstrated in The second phase of the research was conducted to compare the effects of activated Class C and Class F fly ash used at a 20% replacement level to the performance of portland cement mortar (R). This experiment used fly ash obtained with an optimal activation time of 3 h and included the testing of mortars at W/C of 0.3 and S/C of 1. To produce the AC, the required quantities of fly ash  were pre-mixed with tap water, superplasticizer, and, optionally, nanosilica. The resulting fly ash blend was activated by vibro-milling and used for the preparation of mortars as discussed for the first part of the experiment. The preparation of the mortar specimens was based on ASTM C109  and C305To examine compressive strength, cube mortar specimens with side dimensions of 50.8 mm were cast and cured in accordance with ASTM C109 . Test spThe microstructure of activated fly ash was investigated to quantify the process of mechano-chemical activation. Activated Class F fly ash was characterized using X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) for specimens activated for 1, 2, 3, and 24 h . SuperplThe results of the XRD analysis for reference Class F fly ash and specimens activated for 3, 6, and 24 h  are depicted in 3O4) and leads to a considerable concentration of this phase in the activated composition. In the case of Class F ash, there is no evidence of the formation of new nanosized products capable of accelerating the hydration of portland cement systems. The use of inert grinding media such as corundum can be recommended to avoid the contamination and potential reactivity reduction of Class F fly ash.The XRD characterization carried out after the activation process returned an increased intensity of magnetite peaks observed at 30.15° (220); 35.52° (131); 43.17° (400); 57.12° (115), and reflections of iron at 44.55° (110) were observed , as reported in 3A, which is found in a crystalline phase at 32%, 3Al2(SiO4)x3-(OH)x4, where x = 1.5–3) was detected, reducing the C3A content to 11%. It can be observed that the C3A phase was completely converted to katoite after 24 h of milling. However, the follow-up activation for 24 h resulted in the contamination of a specimen with iron at the level of up to 12%. Furthermore, extended milling results in the formation of considerable volumes of iron hydroxide phases such as lepidocrocite γ-FeO(OH) and goethite α-FeO(OH), the contribution of which to the hydration of portland cement systems is not clear. Therefore, it can be concluded that wet mechanical activation in a mill for up to 3 h results in the formation of potentially beneficial nano-seed phases derived from C3A available in Class C fly ash, and the overall process can be described as mechano-chemical activation.Based on XRD, the main cementitious component of Class C fly ash capable of hydration and the formation of nano-seeds is CBased on the heat of the hydration experiment, it was observed that the activation of fly ash in a vibro-mill considerably accelerates the hydration of cementitious systems with fly ash vs. reference mix . The besIt appears that 3-hour activation results in the considerable performance enhancement of blended cement systems. Specifically, the application of activated fly ash enables the acceleration of hydration of portland cement-fly ash blends vs. reference portland cement mortar (R30C), as demonstrated in While all of the mortars were produced at the same W/C ratio of 0.3, the workability of the mortars with activated fly ash was improved with an increase in the activation time of up to 4 h. This is achieved due to a better packing of the particulate systems with activated fly ash and can be used to design concrete mixtures of the same workability at a reduced W/C vs. reference ,21,25,26Likewise, the incorporation of 20% of activated Class C fly ash results in the improvement of the 28-day compressive strength, which was comparable to the performance of the reference portland cement. The main effect of activation is in the improvement of 7-day strength b due to This paper describes a series of experiments evaluating the impacts of mechano-chemically activated fly ash precursors on the rate of hydration, the structure of the hydrated products, and the mechanical properties of mortars.It was proved that the use of mechano-chemical activation of a Class C fly ash precursor with superplasticizer and, optionally, with nanosilica, enables the top-down formation of an activated nano-seed product capable of considerable enhancement of the strength performance of blended cement-based composites. The X-ray diffraction and scanning electron microscopy investigations prove that the activated ash material consists of finely ground and, in the case of Class C fly ash, hydrated nanosized products that are stabilized in a slurry containing chemical admixtures.With isothermal calorimetry, it was demonstrated that the use of activated ash can increase the rate of hydration and, hence, can boost the development of early-age strength. It was found that with activated ash replacement, the 1-day compressive strength of blended binders is increased by up to 26% (for Class F fly ash). Here, the improved packing density from milled particles of fly ash produces a denser composite matrix, which enhances the overall strength development ,4,5,6,7.The activated Class C fly ash was overperforming Class F fly ash in the blended cement systems due to its cementitious properties and also the presence of ultrafine activated ash and nano-seeds. Still, the activation was very effective in Class F fly ash systems, considerably enhancing the compressive strength at the age of 28 days; it can be concluded that for Class F ash, this effect is determined by particle size reduction and improved surface reactivity. Therefore, the boost of the performance of cementitious systems with activated fly ash is due to the presence of ultrafine super-reactive particles of fly ash, nanosilica, and, in the case of Class C fly ash, nano-seed product represented by katoite, with all of these features resulting in the enhancement of performance.Further research is necessary to identify the effects of nano-seeds from an activated fly ash precursor on the composition and morphology of the hardened cement matrix, including the mature systems cured over 28 days, the pore size and permeability modification, as well as the long-term durability performance of developed blended cement composites with an activated component.


As part of the Open Science movement, this study aims to analyze the current state of open access and open data policies concerning the availability of articles and raw data of the journals belonging to the category “Medicine, General & Internal” of the Science Citation Index Expanded.Journal data sharing policies were evaluated through the following variables: possibility of manuscript storage in repositories; reuse policy; publication on a website; and statement regarding complementary material. Subsequently, an analysis of the supplementary material associated with each article was performed through the PubMed Central repository. The study reported was assessed following the STROBE guidelines for observational studies.BMJ Open, JAMA Network Open, New England Journal of Medicine, Lancet and Plos Medicine.This study shows that only one-third of the journals included in the category “Medicine, General & Internal” allow the depositing of their documents in repositories and its reuse, while approximately half of the journals agree to publish the document on a website as well as to deposit supplementary material along with the publication. However, the reality about this last variable is that only 9.5% of the articles analyzed contained supplementary material being the main journals involved, The analysis of the opening policies of the journals concerning data availability in medical research reveals the unequal positioning of publishers towards the sharing of open data, the ambiguity regarding government policies about the obligation to deposit data and the need for ethical and standardization requirements in the typology/format of the data deposited without forgetting the important role that the researcher plays. Further studies based on journals indexed in medical databases other than Science Citation Index Expanded are needed. Medical research affects all people, since all individuals are potential healthcare receivers; research outcomes in this field are therefore of interest for the whole population . In thisOpen Science represents an scenario which includes not only open access, but also concepts such as open data, open source, open methodology or open peer review . As partAs a complementary way to promote transparency and get the most out of medical research, a number of options are available to allow data sharing. While some journals do not accept supplementary files, others place no restrictions . NeverthBased on previous studies, we hypothesize that results will show a lack of homogeneity and protocols for research data sharing. The aims of the present study were to: 1) Analyze the open access and open data policies concerning the availability of articles and raw data of the journals listed in the “Medicine, General & Internal” category of the Journal Citation Reports (JCR); 2) Assess the relationship between journal impact factor and the storage and reuse policies; and 3) Analyze the format of supplementary files regarding the quality of material that may be shared and reused.The report of the observational study was performed based on the STROBE guidelines, being the study units scientific articles. The methodology was developed in three steps following previous studies , 9, howeAs a second step, a subsequent search was performed in the PubMed Central (PMC) repository (the most widely used free full-text repository in biomedicine) to analyze the supplementary material associated with each article of each of the studied journals up to 31 July 2020. Of 165 journals indexed in the “Medicine, General & Internal” category of the Science Citation Index of the JCR, 146 are also present in PMC. Of the 408,899 articles in PMC, a total of 38,761 (9.5%) carried supplementary material. The research strategy used in PMC was designed to retrieve only articles with supplementary material: "journal name"[Journal] .The third step consisted of a quantitative and qualitative analysis of supplementary information. The number and types of files located on the articles with supplementary material were registered even if a single article included several different files. In cases where there was a compressed file , it was opened to check the types of files it contained.Data extraction was conducted manually by three different researchers and compared to agree on a consensus. All the information obtained was entered into an excel sheet, proceeding to its normalization and analysis. A descriptive analysis of the variables was carried out to obtain the frequencies and percentages.Key findings regarding open access and open data policies of the 165 journals belonging to the “Medicine, General & Internal” category are represented in Regarding the “reuse policy”, 40.6% of the journals allowed this possibility, with very similar behavior among the first three quartiles and with a notable decrease for Q4. In contrast, 29.1% of the journals do not allow reuse, while the remaining 30.3% failed to specify this possibility.The variable “possibility of publishing the manuscript on a website”  showed tLastly, the variable "statement of complementary material" was allowed in 53.3% of the cases  while 46.1% of the journals failed to specify this option.BMJ Open, JAMA Network Open, New England Journal of Medicine, Lancet and Plos Medicine  carried supplementary material, being the main journals involved Medicine .The most frequent documents forming part of supplementary material were pdf (48.7%), text (23.3%), images (8.1%), html (7.9%) and spreadsheets (6.0%), containing information mostly referred to genes, molecular markers, and other results from analyzed substances and tissues .The present study analyzed the current state of open access and open data policies of the journals belonging to the category “Medicine, General & Internal” of the Science Citation Index of the JCR and evaluated the types of data deposited by these journals through the PMC repository. Approximately one-third of the journals allow the depositing of their documents in repositories  as well as reuse of the deposited material . Half of the journals agree to publish the document on a website  as well as include supplementary material along with the publication . In all cases, these are journals mostly ranked in quartiles Q1 and Q2. Regarding the actual practice of depositing supplementary material together with the publication, the main journals involved belonged to Q1 and Q2 of the JCR.The availability of data from medical research is a topic of growing interest worldwide. Its importance has recently been evidenced by the urgent need to share information to secure efficient and rapid responses in the past epidemics of the Zika and Ebola viruses and the current pandemic caused by the SARS-CoV-2 , 13, eveThe category “Medicine, General & Internal” is an area in continuous evolution, where journals have improved their representation and impact on the Web of Science in recent years. The number of journals included has progressively increased over the last decade, from 100 journals in 2007 to 165 in 2019, covering medical specialties including general medicine and internal medicine, but also clinical physiology, pain management, military, and hospital medicine.Our findings regarding open access policies show that, of the four variables analyzed, only the possibility of including supplementary material is allowed by more than half of the journals in this category (53.3%). This percentage is higher than the figures reported in other studies carried out in the category of Dentistry, without reaching the values obtained for Emergency Care Medicine , 9.The secondary search through PMC revealed that only 9.5% of the articles contained supplementary material distributed in journals belonging to Q1 57.4%), Q2 (34.7%), Q3 (7.8%) and Q4 (0.1%), respectively. Accordingly, the journals belonging to quartiles Q1 and Q2 contained the highest percentage of articles with supplementary material, which is justified by the responsibility acquired to maintain their quality and provide access to data supporting the published articles. This fact is further evidenced by the observation that the most representative typology (xls) of reusable raw data represents 7.7% in the articles published in Q1 journals, decreasing to 3.3% in Q2 or 5.2% in Q3 . Examini.4%, Q2  as well as reuse of the deposited material —while approximately half of the journals agree to publish the document on a website  as well as deposit supplementary material along with the publication , especially in quartiles 1 and 2. Regarding the depositing of supplementary material together with the publication, 146 journals were in PMC with a total of 408,899 published articles, of which only 9.5% contained supplementary material (mostly pdf and doc files). The main journals involved in the depositing of supplemental material belonged to Q1 and Q2 of the JCR.S1 Table(XLSX)Click here for additional data file.


Glycine max L.) nodulation and N2 fixation. Isoflavones secreted by soybean roots can stimulate signal transduction for symbiotic nodules, thus playing a key role in root nodule development and N2 fixation. The relationship between the inhibition of soybean nodulation, N2 fixation and isoflavones by N is still unclear. In this study, dual-root soybean plants were prepared by grafting, and N or isoflavones were supplied to unilateral roots. The number and dry weight of the soybean nodules, nitrogenase activity, isoflavone concentrations and relative changes in the level of expression of nodulation-related genes were measured to study the response relationship between the N systemic regulation the soybean nodule N2 fixation and changes in the concentrations of isoflavones in its roots. The results showed that N supply to one side of the dual-root soybeans systematically affected the N2 fixation of root nodules on both sides, and this effect began in the early stage of nodulation. Moreover, a unilateral supply of N systematically affected the concentrations of daidzein and genistein on both sides of the roots. The concentrations of isoflavones were consistent with the change trend of soybean root nodule and nodulation-related gene expression level. Treatment with unilateral N or isoflavones affected the soybean nodule N2 fixation and its nodulation-related genes, which had the same response to the changes in concentrations of root isoflavones. N regulates soybean nodulation and N2 fixation by systematically affecting the concentrations of isoflavones in the roots.Nitrogen (N) inhibits soybean ( Glycine max L.) and rhizobium to form root nodules, which can fix N from the air for their own growth  and chalcone synthetase (CHS), that are involved in flavonoid synthesis in soybean roots (CHS) of the flavonoid synthesis pathway in Medicago truncatula, the concentrations of root flavonoids decreased and inhibited the formation of root nodules, while the exogenous supply of naringenin and liquiritigenin, the precursors of flavonoids, restored the normal nodulation and root flavonoid content of Medicago truncatula . Two seedlings were grafted when the cotyledons of the soybean grew to 7–10 cm from the root tip. After 7 days of growth (cotyledon (VC) stage), the part above the grafted interface of downward notched seedlings was cut off, and two roots and one aboveground soybean seedling were prepared. They were then cultured and tested in the field. The dual-root soybean material was prepared using the seedling grafting method of Dual-root soybean was treated in the VC stage, and both sides of the N0 treatment were supplied with N-free nutrient solution. The N100 treatment N-supply side (N+) was supplied with a 100 mg/l N concentration of nutrient solution, and the N-free side (N−) was supplied with N-free nutrient solution. Samples were taken on 1, 3, 7, and 21 days after treatment. After 1 and 3 days of treatment, the number of deformed root hairs was measured by sampling. The root system on both sides was washed with distilled water to remove the sand, and the root system was observed by optical microscopy. The degree of root hair deformation was determined by the number of deformations in every 60 root hairs in the microscope field of vision, and each treatment was repeated six times. After 3 and 7 days of treatment, changes in the expression of genes in the roots were measured by sampling, and the expression of gene changes in the nodules was measured after 21 days of treatment. The root system on both sides was washed with distilled water, the nodules were then removed, and the roots were cut into pieces. The root and nodules were stored at −80°C to measure the level of gene expression, and each treatment was repeated three times. For RNA extraction and quantitative real-time reverse transcription-PCR (qRT-PCR) analysis, total RNA was extracted from root nodules using the TRIzol reagent , and cDNA was synthesized using a RevertAid reverse transcription kit . The primer sequences used for qRT-PCR amplification are shown in 0 treatment supplied N-free nutrient solution on both sides of the two stages. The N100 treatment supplied a nutrient solution with an N concentration of 100 mg/l on the N+ side of the two stages, and the N-side was supplied with N-free nutrient solution. In N100-0 treatment, the N+ side was supplied with nutrient solution with a concentration of 100 mg/l N in stage I and N-free nutrient solution in stage II. The N-side was supplied with N-free nutrient solution in two stages. There were two sampling times: (1) Stage I was treated for 21 days and stage II treatment was initiated at 22 days and ended at 42 days. Samples were taken on days 21 and 42, and the nodule number, nodule dry weight, and nitrogenase activity were determined  of the roots was supplied with nutrient solution that contained isoflavone, and the concentrations of daidzein and genistein were 3.75 mg/l. The untreated side (T-) of the roots was supplied with the nutrient solution without isoflavone. The treatment without isoflavone nutrient solution on both sides was used as a control, which was recorded as I0. The N concentration of nutrient solution supplied on both sides of roots in two treatments was 25 mg/l. On day 7 of treatment, samples were taken to determine the concentrations of daidzein and genistein in roots and root exudates, and there were four replicates. On day 21 of treatment, samples were taken to determine the nodule number, nodule dry weight, and nitrogenase activity, and there were four replicates. The change in level of expression of genes in the roots was measured on days 3 and 7 of treatment, and the levels of expression of changes in the genes in nodules were measured 21 days after treatment. Each treatment was repeated four times. The specific sampling method and determination method were the same as those used in Experiments 1 and 2.Isoflavones were unilaterally applied to a dual-root soybean during the VC stage. In the Ip < 0.05 were considered significant.Data processing and statistical analysis were performed with Microsoft Excel 2016  and SPSS 21.0 . All the data were tested for normality before a one-way analysis of variance (ANOVA) was conducted. The mean differences were compared using Duncan’s multiple range test. Comparisons with 0 and N100 treatments were similar. Compared with the N0 treatment, the nodule number on the N+ side of N100 treatment decreased by 38.14%, and nodule dry weight decreased by 36.84%. After 42 days of N supply, the nodule number and dry weight of the N+ side were significantly different among the three treatments. Compared with the N0 treatment, the nodule number decreased by 26.32 and 17.73% in the N100 and N100-0 treatments, respectively, and nodule dry weight decreased by 30.61 and 14.29%, respectively. The N100 and N100-0 treatments were close to the number and dry weight of the N-side nodules. In comparison with the N0 treatment, nodule dry weight was reduced by 14.29 and 12.24%, and nodule number was reduced by 11.57 and 9.71%, respectively. This indicated that N supply hindered the growth of nodules on the direct contact side, and the growth of nodules without N was also inhibited. The removal of N from the N-supply roots restored the growth of nodules.100 treatment were significantly lower than those of N0 treatment, which decreased by 24.77 and 52.58%, respectively. There was no significant difference between N-side SNA and ARA of N100 and N0 treatments. After 42 days of unilateral N supply, SNA and ARA of N+ side of each treatment were significantly different. Compared with N0 treatment, SNA of N100 and N100-0 treatments decreased by 38.71 and 14.31%, respectively, and that of ARA decreased by 57.45 and 26.54%, respectively. The N-side SNA and ARA of N100 and N100 0 treatments were very similar, and the SNA of the two treatments decreased by 21.17 and 14.92% compared with N0 treatment, while the ARA decreased by 34.43 and 25.31% compared with N0 treatment, respectively. This indicated that the N supply inhibited the nitrogenase activity of the nodules, and the nitrogenase activity was restored after N-free culture. Changes in the N-side were smaller than those in the N+ side.As shown in 100 treatment decreased by 27.95% and N-side by 13.90% compared with N0 treatment. The genistein concentration in N+ side root of N100 treatment decreased by 40.61% compared with N0 treatment, and genistein concentration in N-side decreased by 20.30%. After 7 days of unilateral N supply, the concentrations of daidzein and genistein in the root exudates of the N+ side in the N100 treatment were significantly lower than those in the N0 treatment, while those in the N-side were also smaller than those in the N0 treatment, but the difference was not significant  is involved in the synthesis of isoflavone basic skeleton; the isoflavone synthase gene (GmIFS) is involved in the synthesis of daidzein and genistein, and the chalcone reductase gene (GmCHR) is the key gene for daidzein synthesis  level of expression on the N supply side roots decreased; the daidzein synthesis genes (GmCHS and GmCHR) level of expression on the N-free supply side roots decreased significantly, and the genistein synthesis gene (GmIFS) level of expression decreased slightly. The trend of changes in the three genes of the roots on both sides was consistent with that of the concentrations of root isoflavones, indicating that the reduction of root isoflavone concentrations caused by the N supply was related to their synthesis. In this experiment, the dual-root soybean unilateral N supply method was used to study the systematic regulation of isoflavone concentrations by N. The trend of changes in the concentrations of root and root exudates isoflavones on 7 days after treatment of the N supply was found to be consistent with that of the nodule numbers and nodulation-related genes after 21 days of treatment in soybeans, and the change in root system on both sides was synchronous. This suggested that soybean nodulation is systematically regulated by N, which is closely related to the early synthesis of isoflavones in the root. The unilateral N supply system inhibits isoflavone synthesis and secretion on both sides of the soybean roots, which affects the recognition process of rhizobium and the root system in the rhizosphere and thus affects soybean nodulation.Isoflavones secreted by soybean roots can activate the level of expression of nodulation factor nod genes of rhizobium, which play an important role in the development of nodules and their ability to fix N . Genisteynthesis . After synthesis . In this2 fixation capacity of soybean root nodules , and also increased nodule number and dry weight. It also increased the expression of genes involved in the early nodulation process  and nodule synthesis  in root nodules .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.


Microscopic content segregation is among the important reasons for the anisotropy of mechanical properties in the cast-rolled sheets of the 7B05 aluminum alloy. It is of great significance to study the uniformity of aluminum alloys in terms of the microscopic composition and structure. In this study, a precise method for composition quantification based on micro-beam X-ray fluorescence spectroscopy is established by parameter optimization and a calibration coefficient. Furthermore, this method was applied for exploring and quantifying the relationship between recrystallization and deformation microstructures. The results show that the comprehensive measurement effects of all elements are the best when the X-ray tube voltage is 50 kV, the current is 150 μA, and the single-pixel scanning time is 100 ms. After verification, the sum of differences between the measured values and the standard values for all elements using the calibration coefficient is only 0.107%, which confirms the accuracy of the optimized quantitative method. Three types of segregation indexes in national standards were used to capture small differences, and finally ensure that the segregation degrees of elements are Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al. The quantitative segregation results obtained by the spatial-mapping method show that the difference in the content of Al and Zn is approximately 0.2% between the recrystallization region and the deformation region, the difference in the content of Fe and Ti is 0.018% and 0.013%, the difference in the content of Cr, Cu and Zr is approximately 0.01%, and the difference in the content of Mn is not obvious, only 0.004%. Aluminum alloys are widely used in high-speed train components such as traction beams, corbel beams and buffer beams due to their characteristics of low density, corrosion resistance, weldability and thermal deformation ,2. ThereThe content segregation in different microstructure is an important reason for the difference in mechanical properties. How to mine and quantify the content relationship implicit in the microstructure is a key issue in characterization of the 7B05 material. Common analysis methods for component distribution, such as energy dispersive spectroscopy and electron probe microanalysis, are aimed at a precise test and used for characterization of single points and small regions ,12,13. SDue to the restriction of the production process, the uniformity in workpieces is difficult to guarantee, the abnormally growing recrystallization and element segregation make the plate’s side and intermediate performance present obvious differences. In this paper, a precise method for composition quantification in cast-rolled aluminum alloys based on micro-beam X-ray fluorescence spectroscopy is established to capture small differences between the recrystallization and deformation microstructures by way of parameter optimization and a calibration coefficient. Three kinds of segregation indexes in national standards were used to distinguish the microscopic segregation. Element segregation between recrystallization and deformation microstructures was explored and quantified through spatial mapping of two datasets ,22,23. BThe 7B05 aluminum alloy provided by China Railway Rolling Stock Corporation (CRRC) for commercial sleeper beams was used in the experiment. The elements of 7B05 were measured according to GB/T 20975-2020. Its chemical composition is shown in The element composition distribution of the aluminum alloy section was analyzed by a micro-beam X-ray fluorescence spectrometer . The structure and working principle of the instrument are shown in When the energy of the analytical line of the excited element in the sample is greater than the excitation energy of the spectral line of a coexisting element, the coexisting element will also strongly absorb the analytical line and be excited additionally. In the aluminum alloy element system, such interference from elements absorbing or enhancing effect is also unavoidable. In order to solve the spectral line interference in the process of element quantification, the calibration method for influence factor coefficient will be adopted in this paper. The quantitative method was optimized by using five series of bulk spectral samples with a similar composition to the 7B05 aluminum alloy. Through the linear relationship between the instrument-determined values and the certified values of standard samples of aluminum alloy series, the calibration coefficient (μ) is determined. The chemical composition of B4 series spectral standard samples used in this method is shown in 1, c2] centered on the content median at 95% confidence level.After surface scanning of the aluminum alloy, approximately 1.5 million composition data of a single element were obtained within 150 square millimeters. How to count such a large amount of data, and then accurately characterize the distribution trend of a single element is a key problem. In this paper, three different statistical methods were chosen to quantitatively compare the segregation degree of elements. Firstly, the Original Statistical Distribution Analysis technology (GB/T24213-2009) was used to analyze the scanning data from micro-beam X-ray fluorescence spectroscopy. In this technology, S  is the segregation degree of the content confidence interval [c0 is the median value of the content, and the larger the statistical segregation degree S is, the more serious the element segregation is.In Formula (1), cDS (the degree of segregation) is defined as the ratio of segregation to the overall average value, as shown in Formula (2).0.975 and c0.025 corresponding to the confidence probabilities 97.5% and 2.5%, and x is the overall average value. When the confidence interval is 97.5%, DS is positive segregation, when the confidence interval is 2.5%, DS is negative segregation. The greater the absolute value of DS, the more severe the segregation.In Formula (2), c is the contents cx (segregation ratio).Referring to GB/T37793-2019 quantitative analysis method for dendrite segregation of steel billets, arrange the element content in ascending order, the data with the same content occupying the space in sequence. The total number is N, and the cumulative frequency X is obtained by the sequence number of data divided by N. Equation (3) is the definition of SRmin is the arithmetic mean of the minimum content interval (0~X). Cmax is the arithmetic mean of the maximum content interval (1 − X~1). According to GB/T37793-2019, the cumulative frequency X can be 0.05~0.2, and X is recommended to be 0.15 unless otherwise specified.In Formula (3), SRx is the segregation ratio at cumulative frequency X. CIn order to obtain accurate signal intensity of each element and ensure the reliability of quantitative results, it is necessary to optimize the acquisition parameters. The optimized parameters include the general instrument’s tube voltage, tube current and single pixel acquisition time; the tube voltage and current ranges are 10~50 kV and 100~600 μA, respectively. Due to the large range span, this paper is expected to obtain the change trend of the indicators under different parameters through a set of orthogonal experiments. There are three types of indicators to screen the parameters: the peak-to-background ratio of all element, the relative standard deviation (rsd), and the relative content deviation (rcd). The scanning area was selected as 1 mm × 1 mm with relatively uniform distribution of elements. The experimental parameter settings are shown in The sum of the peak-to-back ratio of all elements under nine groups of conditions is shown in It can be seen from The acquisition voltage optimized by the orthogonal experiment is 50 kV, and the optimal current is 100 or 350 μA. In terms of acquisition time, theoretically, with the increase in single-pixel acquisition time, the relative standard deviation will decrease. When a large-size cast-rolled sheet is measured, considering the limited signal counts of instrument, the single-pixel acquisition time of this material was set to 100 ms to avoid crash failure and ensure better stability. There is a large current span when setting the orthogonal experimental conditions. On the basis of determining the tube voltage (50 kV) and time (100 ms), in order to screen accurate current, seven groups of comparative experiments (50 μA~350 μA) were performed at an interval of 50 μA, with results shown in For optimization of the quantification method, five series of B4 aluminum alloy spectral standard samples were used to draw, and the composition range of standard samples includes the content of each element of the 7B05 alloy. The standard sample was collected in surface analysis under the measurement conditions described in It can be seen from The value of calibration coefficient (μ) was determined by the slope of the fitting in The quantitative analysis of each element in the range of 15 mm × 10 mm is carried out using the optimized quantitative method. In this method, the X direction is the thickness direction, and the number of component arrays is 1440 rows; the Y direction is the length direction, and the number of component arrays is 840 columns. The two-dimensional component distribution is shown in In accordance with the GB/T24213-2009 on general rules of original position statistics, the content distribution analysis of each element at different positions obtained from the surface distribution was carried out. Statistical parameters such as the degree of segregation degree, statistical segregation degree, and segregation ratio of each element in the entire scanning area are obtained. For values of S and SRx, refer to Equations (1) and (3). Values of DS Positive and DS Negative correspond to confidence intervals of 97.5% and 2.5%, respectively, referring to Equation (2). The results are shown in x, DS Positive and DS Negative, as shown in x: Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al; DS Positive: Ti > Fe > Mn > Zr > Cr > Cu > Zn > Al; DS Negative: Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al. The above four segregation indicators show that the segregation of Ti is the most serious, followed by Fe, and the distributions of Al, Zn, and Zr are the most uniform. The segregation degrees of Cr, Cu and Mn are similar, the S indicates that three elements are difficult to separate , and the SRx and DS Negative indicates that three elements are relatively different. In summary, the results of four segregation evaluation indexes are basically consistent, which can be used to characterize small segregation difference in a complementary manner; the segregation degree of element in 7B05 is Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al.Three different statistical methods are chosen to quantitatively compare the segregation degree of elements: S, SRThe frequency distribution diagram of element content is shown in Furthermore, to explore the variation law of the content along the thickness direction in the aluminum alloy rolled sheet, the scatter diagram and fitting diagram of the average content are shown in Application results in In this paper, 60 positions with gray value differences were selected, respectively, and single-point test was carried out on them. The average content was obtained after three measurements at each position. These test results were divided into categories A and B according to gray value. Class A represents a low gray area, and Class B represents relatively high grayscale value. As shown in Since the content and grayscale data are collected from two different kinds of scale and type, it is difficult to use point-to-point to explore the correlation between the two. This paper will explore rules between the two datasets by the inter-micro-area spatial-mapping method, and quantitatively express the degree of correlation between the two. The component data and grayscale data set in the range of 1 mm × 1 mm were divided into 16 regions, and the data in same region showed a one-to-one correlation, as shown in It can be seen from (1)Considering the optimal measurement effect of all elements, the final measurement conditions are determined as follows: the X-ray tube voltage is 50 kV, the current is 150 μA, and the single-pixel scanning time is 100 ms.(2)Using the calibration coefficient and after verification with the E323C standard sample, the sum of differences between the measured values and the standard values for all elements is only 0.107%.(3)The segregation degree of element in 7B05 is Ti > Fe > Cr > Cu > Mn > Zr > Zn > Al; When the difference in element segregation degree is not large enough to distinguish, the three complementary indexes can be used to accurately characterize element segregation.(4)The distribution of elements presents a band-like segregation, which is similar to the microstructure morphology. Al, Cr, Ti, and Zr exist in the form of microscopic positive segregation, and Zn, Cu, Mn, and Fe exist in the form of microscopic negative segregation in the recrystallization region. The difference in the content of Al and Zn is approximately 0.2% between the recrystallization region and the deformation region, the difference in the content of Fe and Ti is 0.018% and 0.013%, the difference in the content of Cr, Cu and Zr is approximately 0.01%, and the difference in the content of Mn is not obvious, only 0.004%. Element segregation may be related to the distribution of the precipitated phase at grain boundaries.


The aim of this ecological study is to evaluate correlations between the number of COVID-19 vaccine doses administered in three Italian provinces—one in the south, one in the center and one in the north of the country—and the registered numbers of COVID-19 cases in the same areas. The period of January 2021–September 2022 was considered, with specific analysis for fractions of times corresponding to the spread in Italy of the different SARS-CoV-2 variants. The results confirm the reduction of the effectiveness of the vaccines in preventing new COVID-19 cases in Italy, regardless of latitude, after the appearance of the first omicron variants. The new variants omicron 4 and 5 showed an extremely high spread during the Italian summer months; fortunately, the effects of the vaccinations in preventing new cases was improved compared to the previous omicron variants, showing a negative correlation between the new COVID-19 cases and the number of vaccine doses administered. The vaccination campaign against COVID-19 begun in Italy at the end of December 2020 ,4. At thThe aim of the present study is to evaluate correlations between the number of COVID-19 vaccine doses administered in three Italian provinces and the registered numbers of COVID-19 cases. Specific sub-analyses for the periods of the pandemic corresponding to the dominancy of specific SARS-CoV-2 variants have been also conducted.The present paper is an ecological study examining crude correlations between the number of COVID-19 vaccine doses and the reported COVID-19 cases in three Italian provinces.The provinces of Palermo , Rome  and Milan  were selected as, respectively, representatives for the south, the center and the north of the country.The data of new COVID-19 cases have been registered on a daily basis in Italy since the beginning of the pandemic and reported by the Italian National Institute of Health  and theth December 2020, i.e., the first day with data on the vaccine doses administered in Italy [We tested Pearson’s r correlations in Microsoft Excel in order to correlate the data of the vaccines’ doses with the number of COVID-19 cases. We started from the 28in Italy , and we A period of 30 days was arbitrarily established to appreciate the significant effect of vaccine administration on the prevention of the registered SARS-CoV-2 infections, in order to consider a relevant immune response induced in the vaccinated subjects .Considering the three provinces together, with a total population of 8,840,156, the peak of the new daily cases of SARS-CoV-2 infections was reached in March 2021 for the alpha variant, with 2606.5 new daily infections on average, corresponding to an incidence per 10,000 inhabitants of 2.95. In that month, the highest incidence of 3.50 per 10,000 was registered in Milan.In terms of the delta variant, the peak appeared to occur in November 2021, with a total of 1235.8 and an average daily incidence of 1.40 new cases per 10,000 inhabitants, even if it cannot be excluded that the omicron 1 variant, which appeared in Italy at the end of November 2021, contributed to these numbers. In November 2021, the highest incidence was reported in Rome, with an average of 1.65 new daily cases per 10,000 inhabitants .Since December 2021 and until June 2022, the omicron 1, 2 and 3 variants were the most prevalent SARS-CoV-2 variants in Italy, and the highest number of new daily infections was reached in the month of January 2022, with 20,173.5 new daily cases on average considering the three Italian provinces together, representing an incidence of 22.8 cases per 100,000 inhabitants. The highest incidence in January 2022 was reported in Milan, with an average of 28.38 new cases per 10,000 inhabitants per day. Finally, in the period July–September 2022, the new omicron 4 and 5 variants spread in Italy, with a peak of 10,270.1 mean daily cases in July and an incidence of 11.62 new infections per day per 10,000 inhabitants. The highest incidence in July 2022 was reported in Rome, with a rate of 12.67 new daily cases per 10,000 inhabitants on average .Regarding the vaccine doses, the highest number of vaccinations were administered in the month of June 2021 , and an overall r value considering the three provinces together of −0.266 .This Italian ecological study is a further demonstration of the overall effectiveness of the anti-COVID-19 vaccination campaign ,3,4, as The delta variants spread in Italy during summer 2021, with higher infectivity compared to alpha variants , and resOn the contrary, when looking at the period of the spread of the first omicron 1, 2 and 3 variants in Italy, i.e., December 2021–June 2022 , it seemFinally, the data related to the recent omicron 4 and 5 variants that spread in Italy during summer 2022, are interesting . It seemFortunately, negative correlations with the number of vaccine doses administered, even if quite weak, reappeared for new cases of omicron 4 and 5; this is possibly an effect of the administrations of the fourth booster vaccine doses after June 2022 to elderly and fragile subjects and healthcare workers in particular. Nevertheless, it should also be considered that the negative correlations between the most recent omicron variants infections and vaccine doses can be strengthened by the occurrence of previous SARS-CoV-2 infections, and in particular of omicron 1–3 infections ,19.This ecological study has various limitations: first of all, its design is unable to prove any association, but only aimed to suggest correlation patterns among variables . There aThe results of this ecological study conducted in three Italian provinces confirm the reduction of the effectiveness of the COVID-19 vaccines in preventing new SARS-CoV-2 infections, regardless of latitude, after the appearance of the first omicron variants in Italy. The new variants omicron 4 and 5 showed a very high spread during the Italian summer months; fortunately, negative correlations between new COVID-19 cases and the number of vaccine doses have been detected, stressing the importance of continuing with the vaccination campaign, including the fourth booster doses, possibly with omicron-adapted vaccines.