The photocorrosion of a nanoporous carbon photoanode, with low surface functionalization and high performance towards the photoelectrochemical oxidation of water using simulated solar light, was investigated. Two different light configurations were used to isolate the effect of the irradiation wavelength (UV and visible light) on the textural and chemical features of the carbon photoanode, and its long-term photocatalytic performance for the oxygen evolution reaction. A complete characterization of the carbon showed that the photocorrosion of carbon anodes of low functionalization follows a different pathway than highly functionalized carbons. The carbon matrix gets slightly oxidized, with the formation of carboxylic and carbonyl-like moieties in the surface of the carbon anode after light exposure. The oxidation of the carbon occurred due to the photogeneration of oxygen reactive species upon the decomposition of water during the irradiation of the photoanodes. Furthermore, the photoinduced surface reactions depend on the nature of the carbon anode and its ability to photogenerate reactive species in solution, rather than on the wavelength of the irradiation source. This surface modification is responsible for the decreased efficiency of the carbon photoanode throughout long illumination periods, due to the effect of the oxidation of the carbon matrix on the charge transfer. In this work, we have corroborated that, in the case of a low functionalization carbon material, the photocorrosion also occurs although it proceeds through a different pathway. The carbon anode gets gradually slightly oxidized due to the photogeneration of O-reactive species, being the incorporation of the O-groups responsible for the decreased performance of the anode upon long-term irradiation due to the effect of the oxidation of the carbon matrix on the electron transfer. Solar energy conversion and storage is a research topic at the forefront of technology that has attracted the attention of scientists across various disciplines. The use of sunlight for the catalytic splitting of water to produce hydrogen and oxygen is a key process for solar fuel production systems towards a sustainable utilization of electricity generated from renewable energy resources. From the large-scale application point of view, water breakdown by electro- and/or photo-assisted methods is hampered by the low overall efficiency of the reaction and the scarcity and high cost of the precious metals typically used as catalysts and/or photocatalysts ,2,3,4,5.2, does not to absorb photons with wavelengths longer than 387 nm , thus much of the sunlight is wasted as the exploitation is reduced to ca. 4%. For these reasons, research on the use of abundant materials with improved harvesting features across the visible region that can serve as efficient catalysts in such systems is currently receiving much attention [2 and other photocatalysts [Most commonly used materials in photocatalytic processes are semiconductors, however they usually present low photonic efficiencies under solar light. For instance, one of the benchmark materials, TiOttention ,7,8. Extatalysts ,10,11. Aatalysts ,13,14,15atalysts ,17,18,19On the other hand, we have recently reported the photochemical activity of metal-free nanoporous carbons in the absence of semiconductors under various irradiation conditions ,22,23,24Following the application of nanoporous carbons in photochemical reactions, we have recently explored the use of nanoporous carbons as photoanodes in photoelectrochemical water splitting ,25,26. DTo further clarify the issue of photocorrosion observed in carbon anodes, we have investigated a nanoporous carbon with low functionalization and investigated its ability to photocatalysis the oxidation of water after long irradiation periods, as well as the extent of surface photocorrosion due to the long-term light exposure. An extensive surface and textural characterization of the carbon anodes after illumination under different conditions was made, trying to link the effect of the irradiation wavelength with the deactivation of the anode under long illumination periods, and particularly with the photoinduced modifications in its specific textural, chemical, and structural features.In a previous study, we reported the performance of nanoporous carbon photoanodes for the photocatalytic and photoelectrochemical oxidation of water under solar light, using carbons from various origins and rich surface chemistry ,26. DataIn this work, we extend this study to nanoporous carbons with low surface functionalization, where the deactivation (if any) should not be attributed to the redox reactions involving the heteroatoms and surface groups decorating the carbon matrix. Details on the textural and chemical characteristics of the nanoporous carbons used as photoanodes, as well as their performance towards the photocatalytic and photoelectrochemical oxidation of water using simulated solar light have been presented in detail elsewhere ,23,26. W2 concentration in the electrolyte using a sensor.For all the carbons, the transient photocurrent curves upon on/off illumination presented a square-shaped profile b, with a2 were obtained for the highest potentials and the best performing photoanode. Interestingly, a higher photocurrent density was obtained for the nanoporous carbon with a low surface functionalization (sample NC). This contrasts with our previous study [The potential onset of the photocurrent was quite similar for all the carbon anodes varying between +0.6 and +0.8 V vs. Ag/AgCl a; these us study  where th2 carbon clusters due to π-π* and σ-π transitions involving zig-zag, carbyne-like sites and other intermediate states [2 domains of the carbon anode, and transferred to electron acceptors present in the medium .Beyond surface wetting and conductivity, the carbon must have photoactive sites inside the pores at which carbon/light/water interactions can take place. Such photoreactive sites would be located at the edges of the basal planes, either associated with surface functionalities or to free edge sites linked to various configurations (carbyne-like and carbene-type) . Hence ue states , charge-e states ,29. The Given that carbon NC was the best performing photoanode a, in fur2 released in the electrodes, most likely arising from the carbon black and/or the binder used in the preparation of the electrodes.To evaluate the origin of this behavior in sample NC, the surface chemistry of the photoanodes before and after exposure to light and polarization was analyzed by temperature programmed desorption coupled to mass spectrometry, TPD-MS . Complex2 desorbed, associated with the decomposition of carboxylic-like groups. Notwithstanding, to disregard the effect of the carbon additives of the electrodes, we considered a different approach for the irradiation of the carbon.Despite this, data show a clear trend with increasing amounts of O-containing groups in the carbon anodes exposed to light indicating that the carbon material is slightly oxidized ; this isTo investigate the effect of the sunlight on the textural and chemical features of the carbon electrodes disregarding the interference of the binder and the carbon black conductive additive used in the fabrication of the photoanodes, an aqueous suspension of the nanoporous carbon was irradiated for 2 h. Furthermore, two different configurations were used, with filters to cut-off the irradiation below 360 nm , to explore the effect of the wavelength of the irradiation source on any likely changes induced in the nanoporous carbon as a result of light exposure. The characterization of the carbon material after irradiation under these conditions was carried out by XPS , Table 32 due to the decomposition of O-groups are compiled in 2 was detected for both irradiated samples, whereas the increase in the amount of CO evolved accounted for 12%–15%. The temperature of the CO2 (between 200–400 °C) and CO (above 500 °C)—Data from the TPD-MS study corresponding to the release of CO and COs and O 1s XPS profiles and the composition of the carbon after light exposure are shown in The C 12-evolving groups by TPD-MS showed an opposed trend  ,34. Thus2-evolving groups detected by TPD-MS is due to the overall oxidation of the carbon electrode by the O-radicals. On the other hand, the surface reducing effect of the carboxylic groups is more remarkable at the carbon/water interface, where the photogenerated electrons are formed (thus explaining the relative distribution of groups detected by XPS).To understand this behavior, we must consider the redox reactions likely occurring upon irradiation of the carbon anodes at the carbon/water interface. As above-mentioned, in carbons of low functionalization, low to medium range excitons are formed upon light exposure due to π-π* and σ-π transitions. The anodic photocurrent detected for this carbon with the generation of oxygen confirmed the generation of reactive vacancies that react with water, producing oxygen and leaving electrons free to react with other species in the medium such as oxygen, water, or the electrode material itself. In this regard, we have confirmed the formation of O-radicals (hydroxyl and superoxide) upon irradiation of an aqueous suspension of sample NC . Thus, tThe fact that we observed a similar distribution of surface groups in both lamp configurations indicates that the type of the reactions is more dependent on the nature of the carbon anode and its ability to photogenerate reactive species in solution than on the wavelength of the irradiation source.The slight oxidation of the carbon matrix (even if subtle) is responsible for the decreased efficiency of the carbon photoanodes as photo- or electrocatalysts after long illumination periods, as high oxygen contents are detrimental for the electrical conductivity of carbon materials, and thus favor current losses.2 activation of bituminous coal was selected for the preparation of the photoanodes. The choice of the material was based on its reported photochemical activity towards the oxidation of pollutants in solution [4)2S2O8 in 4 N H2SO4 at room temperature (ca. 1 g of carbon per 10 mL solution) and stirred overnight (sample NCox). For the preparation of the photoanodes a slurry of the nanoporous carbon, polyvinylidene difluoride as binder, and a carbon black conductive additive (ratio 85:10:5) in N-methyl-2-pyrrolidone was coated on a 1 cm2 Ti foil collector. The electrodes were dried in air at 120 °C before usage. For comparison purposes, the photocatalytic performance of the photoanode prepared from sample NC was compared to that of other nanoporous carbons from a previous study  [A nanoporous carbon (sample referred to as NC) obtained from COsolution ,23. The ple BAX) .2) was used as irradiation source; a pyrex filter (cut-off below 360 nm) was employed to isolate the contribution of visible light in the solar simulator. The photoanodes were immersed in 20 mL of an aqueous electrolyte  and purged with N2 before the illumination. The transient photocurrents of the carbon photoanode under on/off illumination were recorded at constant potentials between 0 and +1.5 V vs. Ag/AgCl, in a potentiostat (Biologic). Dark current equilibrium at the bias potential was allowed before the irradiation. The O2 concentration in the electrochemical cell was measured using an oxygen sensor immersed in the electrolyte. The cyclic voltammetries, at a potential rate of 20 mV/s, of the carbon photoanodes before and after light exposure were also recorded.A standard three-compartment cell with an optically flat quartz window on the side and consisting of the nanoporous carbon photoanode as working electrode, a graphite rod as counter electrode, and a saturated Ag/AgCl as reference electrode were used. A solar simulator .To evaluate the surface modification of the carbon photoanode by the effect of the solar irradiation, water suspensions of powders of the carbon material (ca. 1 g/L loading) were exposed to irradiation for 2 h under continuous stirring. The photoreactor consisted of a high pressure mercury lamp  surrounded by a cylindrical, double-walled jacket cooled by flowing water (to prevent overheating). Two different irradiation conditions were studied to evaluate the wavelength dependence of the surface modification: the photoreactor with a quartz jacket . The incident photon flux in the photoreactor was measured by chemical actinometry [2 and N2 at 273 and 77 K, respectively, were recorded in volumetric analyzers (Micromeritics). The N2 data was used to calculate the specific surface area (SBET) and total pore volume . The narrow microporosity was evaluated from the CO2 data using the Dubinin-Radushkevich formulism. Ultrahigh purity gases were provided by Air Products.Before the characterization, the carbons were degassed under vacuum at 393 K for 17 h. The high-resolution adsorption isotherms of CO2) was followed by the mass spectrometer. XPS for the analysis of the C 1s and O 1s core level signals were collected in a SPECS spectrometer by using Al Kα (1486.74 eV) radiation with a power of 100 W in the constant analyzer energy mode. Spectra of dried powdered samples were recorded with constant pass energy values of 50 eV, using a 720 μm diameter analysis area. During the processing of the XPS spectra, energy values were referenced to the C 1s peak of adventitious carbon located at 284.6 eV. The PHI ACCESS ESCA-V6.F software package was used for acquisition and data analysis. A Shirley-type background was subtracted from the signals. Recorded spectra were always fitted using Gauss–Lorentz curves, in order to determine the binding energy of the different element core levels more accurately. The error in BE was estimated to be ca. 0.1 eV.Samples were chemically characterized by elemental analysis. The determination of carbon, hydrogen, and nitrogen was carried out by a LECO CHNS-932 (ASTM D-5373), while oxygen was directly measured in a LECO VTF-900 CHNS-932 microanalayzer. The samples were dried under vacuum at 393 K for 17 h before the analysis. Temperature programmed desorption (TPD) was measured in a chemisorption analyzer (Autochem 292) connected to a mass spectrometer (TPD-MS) for gas analysis, obtaining the gas evolution profiles as a function of temperature. About 10 mg of carbon sample were heated up to 1073 K (10 K/min) under a constant argon flow (50 mL/min). The composition of the evolved gases . The nanoporous carbon photoanode exhibited good performance towards the oxygen evolution reaction under simulated solar light, with an onset of the photocurrent at a low overpotential (ca. +0.8 V vs. Ag/AgCl). The loss in efficiency after 2 h of irradiation suggested the occurrence of photo- and/or electro-corrosion of the anode, as already reported for highly functionalized carbon anodes. As opposed to the latter, where the drop-in performance was attributed to the reduction of some groups in the carbon surface, the characterization of the carbon photoanode revealed that the photocorrosion of carbon anodes of low functionalization proceeded through a different pathway. The carbon matrix gets slightly oxidized, with the formation of carboxylic and carbonyl-like moieties, whereas the porosity remained unchanged. The oxidation of the carbon matrix occurred due to the oxygen reactive species formed upon the decomposition of water during the irradiation of the photoanode. Similar surface modifications of the carbon were obtained in both lamp configurations, indicating that the photoinduced surface reactions depend on the nature of the carbon anode and its ability to photogenerate reactive species in solution, rather than on the wavelength of the irradiation source. The surface changes upon irradiation of the carbon photoanode are responsible for its decreased efficiency throughout long illumination periods, due to the effect of the oxidation of the carbon matrix on the conductivity.


With the extensively spread of industrialization in the world, noise exposure is becoming more prevalent in the industrial settings. The most important and definite harmful effects of sound include hearing loss, both permanent and temporary.This study was designed aimed to use the C5 algorithm to determine the weight of factors affecting the workers’ hearing loss based on the audiometric data.This cross-sectional, descriptive, analytical study was conducted in 2018 in a mining industry in southeastern Iran. In this study, workers were divided into three exposed groups with different sound pressure levels (one control group and two case groups). Audiometry was conducted for each group of 50 persons; hence, the total number of subjects was 150. The stages of this study include: 1) selecting factors (predictive) to check and weigh them; 2) conducting the audiometry for both ears; 3) calculating the permanent hearing loss in each ear and permanent hearing loss of both ears; 4) classifying the types of hearing loss; and 5) investigating and determining the weight of factors affecting the hearing loss and their classification based on the C5 algorithm and determining the error and accuracy rate of each model. To assess and determine the factors affecting the hearing loss of workers, the C5 algorithm and IBM SPSS Modeler 18.0 were used. SPSS V.18 was used to analyze the linear regression and paired t-test tests, too.The results showed that in the first model (SPL <70 dBA), the 8KHz frequency with the weight of 31% had the highest effect, the factors of work experience and the frequency of 250Hz each with the weight of 3%, had the least effect, and the accuracy of the model was 100%. In the second model (SPL 70–80 dBA) the frequency of 8KHz with the weight of 21% had the highest effect, the frequency of 250Hz and the working experience each had the lowest effect with the weight of 7% and the accuracy of the model was calculated as 100%. In the third model (SPL >85 dBA), the 4KHz frequency with the weight of 31% had the highest effect, and the work experience with a weight of 1% had the lowest effect, and the accuracy of the model was 94%. In the fourth model, the 4KHz frequency with the weight of 22% had the highest effect and 250Hz and age each with the weight of 8% had the lowest effects; the accuracy of this model was calculated to be 99.05%.During investigating and determining the weight of the factors affecting hearing loss by the C5 algorithm, the high weight and effect of the 4KHz frequency were predicted in hearing loss changes. Considering the high accuracy obtained in this modeling, this algorithm is a suitable and powerful tool for predicting and modeling the hearing loss. Significant evidence exists indicating that noise is among the most prevalent kinds of occupation-related dangers in today’s world. Research shows that, each day in Europe, about 450 million people experience noise levels of minimum 55 dB (A), 113 million individuals are exposed to a noise level of at least 64 dB (A), and 9.7 million persons experience the noise levels of 75 dB (A) or higher . AccordiExcessive noise causes physiological complications such as hypertension, adrenaline production, an increased risk of heart attack, high blood pressure, changes in respiratory rate, and the amount of consumed oxygen, affecting the auditory system, and increased stomach and intestinal activities, and other social and economic effects, and influences the efficiency and effectiveness of the exposed people. It also leads to interferences with verbal communication and perceptions of warning signs and affects the safety and performance of individuals 5. Althou6The extreme sound may lead to temporary or permanent hearing threshold change with the macroscopic  and microscopic  effects in the ear . HearingNoise-induced hearing loss (NIHL) is a public health problem happening during daily life, which is primarily disregarded, but may lead to the intense morbidity as it is developed. Noise-induced hearing loss (NIHL) is a complex disorder that may possibly be affected by environmental and genetic factors . NIHL isThe National Institute of Occupational Safety and Health (NIOSH), USA, still classifies the noise-induced hearing loss among the top ten work-related problems, which involves at least 11 million workers in the US. It was reported in the recent studies that despite the hearing conservation programs, employees continue to develop NIHL . OccupatData mining (DM) is an interdisciplinary subfield of computer science. It is the computational procedure of discovering patterns in large data sets, which include the methods at the intersection of artificial intelligence, statistics, machine learning, and database systems. To extract information from a data set and convert it into an understandable structure for further use are the general objectives of the DM process. Such information may involve data classification and prediction of outcomes after an intervention, or it may investigate the association, group, or detection of variable deviation . Our choRule sets are preferred in many applications, because of simplicity and easiness for understanding compared to the decision trees. C5 can create classifiers demonstrated either as decision trees or as rule sets. C5 algorithm follows the rules of the algorithm of C4.5, as well as the rules of the ID3 algorithm. C5 algorithm involves many features, as the large decision tree can be considered as a set of rules easy to understand, providing the knowledge on noise and missing data. In classification technique, problem of over fitting and error pruning are solved and the C5 classifier can determine the relevant and irrelevant attributes in classification. The algorithm C5 indicates that how the rule sets are created with improved features while generating fewer rules, therefore, compare to other classifiers, memory usage is low .Because hearing loss is one of the most common noise exposure impairments, it results in high costs for workers in the industry and exposed individuals. Considering that, fewer studies exist in the world conducted on weighting and prioritizing factors affecting the workers hearing loss based on the audiometry data using the C5 algorithm, this study was designed to examine the following objectives:Determining the workers’ equivalent sound level.Determining the hearing loss of both ears.Determining the weight of the factors affecting hearing loss based on the C5 algorithm.Determining the error & accuracy rate of the C5 algorithm.This study was conducted in mining industry in southeastern Iran, for which according to the individual’s equivalent sound level and previous studies, as well as the type of algorithm used in hearing loss modeling, totally three groups (one control group and two case group) was considered. For each group, 50 people were assigned . Thus, the total number of subjects under study was 150 .This is a cross-sectional, descriptive-analytic prospective study. The general stages in orders are as the following: 1) choosing the predictive factors; 2) performing the audiometry and calculating the permanent hearing loss of each ear and then overall hearing loss; 3) classifying the types of hearing loss ; 4) determining the weight of factors effective on the hearing loss based on the C5 algorithm; and 5) determining the error and accuracy rate . Four va21Using Clinical Audiometer CA 120 made in Denmark, pure-tone hearing thresholds at 250, 500, 1000, 2000, 4000, 6000 and 8000 Hz were recorded [At first, the permanent hearing loss of the left and right ear was calculated separately, for this aim, the hearing loss in each 4 important frequencies of 500, 1000, 2000, and 4000 was entered in the related equation after the fraction of age, and the rate of permanent hearing loss caused by sound was calculated (Equation 1). Subsequently, Equation 2 was used to calculate the total permanent hearing loss .Equation 1:TL: Hearing loss at the considered frequency per ear (dB)NIHL: Permanent hearing loss caused by sound (dB)Equation 2:t:NIHL Total permanent loss in both ears (dB)b:NIHL permanent loss of the stronger ear (dB)p:NIHL permanent loss of the poor ear (dB)Hearing loss classification based on the WHO categorization is such that hearing in the range of 0–25 dBA was classified as normal hearing, 26–40 dBA as a mild loss, 41–60 dB as average loss, 61–80 dBA as severe loss and over 80 dBA was classified as deep loss [In this method tree, structure was used to create the classification models. A dataset is divided in this method into smaller subsets. Leaf node provides a decision. The decision trees classify the cases based on feature values of instances. Each node indicates a feature in an instance in a decision tree, which is to be classified, and each branch provides a value. Based on the feature values Classification of Instances starts from the root node and it is sorted. Decision trees can control categorical and numerical data  Figure .The objective is to discover classification rules determining the class label of any object (Y) from the values of its attributes (X). Each internal node (non-leaf node) provides a test condition on an attribute, an outcome of the test is obtained from each branch, and a class label is represented by each leaf node . Let a node N provides the tuples of partition D. The attribute with the highest information gain is selected as the splitting attribute for the node N. Through this attribute the information needed to classify the tuples in resulting partitions is minimized and the least randomness in these partitions is reflected. The expected information needed to classify a tuple in D is given as the following :Equation 3:iP represents the probability that an arbitrary tuple in D is associated with class iC and is estimated by |i, DC|/|D|. Info D is the average amount of information required to determine the class label of a tuple in D. Info (D) is also recognized as the entropy of D. Suppose that we to attempt to partition the tuples in D on an attribute A having υ distinct values {1, a2,…,aυa}. The obtained partitions are associated to the branches of the node N. InfoA (D) is the expected information needed to categorize a tuple from D based on the partitioning by A.Where Equation 4:j th partition. The information gain is explained as the difference between the original information necessity (i.e. based on just the proportion of classes) and the new necessity (i.e. obtained after partitioning on A).The term Equation 5:The attribute A with the highest information gain, Gain (A), is selected as the splitting attribute at node N .In classification algorithms that are used to categorize discrete-type output factors, the evaluation criteria such as accuracy, confusion matrix, sensitivity, and attribute are used. In this study, two criteria of accuracy and confusion matrix were used. The confusion matrix is a square matrix with the dimensions equal to the number of output factors classes. In this matrix, the main diameter represents the percentages that were correctly predicted. According to Equation 6, the accuracy of the model is actually the ratio of the correct predicted cases to the total cases .Equation 6:The Ethics Committee of Kerman University of Medical Sciences approved the present work ethically (ID: IR.KMU.REC.1396.2458). All participants signed a consent form.Using Statistical Package for Social Sciences V.18 (SPSS) , the collected data were analyzed. Mean, standard deviation and correlation coefficient were analyzed using linear regression statistical and paired t-test tests. Moreover, modeling the hearing loss changes was performed using IBM SPSS Modeler 18.0.The demographic data of participants are showed in Table The first group was exposed to an equivalent sound level of less than 70 dB. The second group was exposed to the equivalent sound level of 70 to 80 dB, and the third group was exposed to the equivalent sound level over 85 dB. The mean and standard deviation of the equivalent sound level for the first, second and third groups were 70 ± 3 dBA, 77.62 ± 4.43 dBA, and 89.7 ± 3.03 dBA, respectively.The results of the workers’ hearing loss in both ears based on the severity of hearing loss are provided in Table In this study, four different models of hearing loss were calculated. In the first model, the Audiometric data of the first group workers (SPL <70 dBA), in the second model the Audiometric data of the second group workers (SPL 70–80 dBA), in the third model, the audiometric data of the third group workers (SPL >85 dBA), and ultimately, in the fourth model the total audiometric data of workers in the three groups were modeled.Inserting the results of the above factors for the first model (n = 10) in IBM SPSS Modeler 18.0, the results are obtained as shown in Figure The model predicted correctly the severity of hearing loss for all people with the normal and mild hearing loss, and the accuracy of the C5 algorithm of 100% in this modeling.The results of modeling the hearing loss changes in the second model (n = 10) are shown in Figure The model predicted correctly the severity of hearing loss of all people with normal, mild and moderate hearing loss, and the accuracy of the C5 algorithm was obtained 100% in modeling hearing loss changes.The results of modeling the hearing loss changes in the third model (n = 10) are provided in Figure The model predicted accurately the severity of hearing loss of all people with moderate & severe hearing loss; 6.67% of the people with mild hearing loss were mistakenly predicted as the normal and 6.9% of those with normal hearing loss, were incorrectly predicted with mild hearing loss. The accuracy of the C5 algorithm was 94%.Inserting the results of the effective factors for the fourth model (n = 30) in the software, the results are obtained as shown in Figure The model precisely predicted the severity of hearing loss for all people with mild, moderate, and severe. 0.95 percent of those with normal hearing loss, were incorrectly predicted as mild. The accuracy of model was 99.33% with an error rate of 0.67%.This study aimed to use the C5 algorithm to determine the weight of factors affecting workers’ hearing loss based on the audiometric data. The mean exposure to equivalent sound level for the first, second and third groups was 70 ± 3 dBA, 77.62 ± 4.43 dBA, and 89.7 ± 3.03 dBA, respectively. There was a significant statistical difference between age and work experience with hearing loss in the first and second groups, so that in the first group between age and hearing loss, P = 0.008, R = 0.385 and in the second group, P = 0.008, R = 0.394. There was a statistically significant difference between work experience and hearing loss in the first group  and second group , too. However, in the third group, there was no significant statistical difference between age and working experience with hearing loss, as between the age and hearing loss, R = 0.189, P = 0.277, and between work experience and hearing loss, R = 0.28, P-value = 0.076. Based on the correlation and linear regression, there is a statistically significant difference between hearing loss and sound in all the subjects (n = 150), .In a study conducted by Aghilienejdad et al. to investigate the effect of work environment noise on workers’ hearing at small workshops in Tehran, in 2007, 109 people among the employees in the workshops with less than 50 workers were selected as a case group and the same number were selected as the control group considering all the aspects. In the case group, according to regression model coefficients and regression analysis results, the equivalent sound level was as the first factor, age, and work experience was considered as the next predictor of hearing loss. For the working people in the case group, the progression of hearing loss was associated with the increased work experience . The resAccording to C5 modeling, in the first model (SPL <70 dBA), the 8KHz frequency had the highest weight 31%), and the work experience and 250Hz each with a weight of 3% had the least effect , age and work experience. This is despite the fact that most studies for modeling the hearing loss changes in the world report only the error & accuracy rate and did not mention the weight and effect of each of these factors. Among the constraints of this study are the problems with the industry and not cooperating of some people in conducting audiometric tests.This article aimed to investigate the hearing loss and weight the factors affecting it by using C5 algorithm. According to the results in the first model, with the predictive factors , the frequency of 8KHz with the weigh of 31%, had the highest effect and the factors of work experience & frequency of 250Hz each with a weight of 3% had the lowest effect. The accuracy of the predicted hearing loss model was also 100%. In the second model, considering the predictive factors, the frequency of 8KHz with a weight of 21% had the highest and the work experience & frequency of 250Hz each with a weight of 7% had the lowest effect; the accuracy of the predicted model was 100%. In the third model, the frequency of 4KHz with the weigh of 31% had the highest effect and the work experience with a weight of 1% had the lowest effect and the accuracy of the predicted model was 94%. Ultimately, in the fourth model, the frequency of 4kHz with the weight of 22% had the highest effect and the frequency of 250Hz and the age each with a weight of 8% had the lowest effect and the accuracy of the predicted model was 99.33%. Therefore, considering the high accuracy of the predicted models in the groups, the C5 algorithm is recommended as an appropriate and powerful tool for predicting and modeling the hearing loss.


Surface lifting was performed in 20.2% of patients, SMAS-lifting – 49.0%, SMAS-lifting with a three-level endoscopic assist lift of the lower face zone was performed in 30.8% of women. Before the surgery in 13.2% of cases, I degree of involutional changes in facial skin was registered, 47.9% – grade II, 38.9% – grade III. Patients were divided into two comparable groups. With the standard preparation without additional drug correction, 299 women (64.9%) were operated on in the preoperative period, they made up a comparison group. The main group included 162 (35.1%) women who underwent therapeutic conditioning before the lifting operation . Instrumental evaluation of the skin dermal microcirculation was performed using laser Doppler flowmetry and estimation of transcutaneous oxygen tension. In the blood plasma, the parameters of free radical processes (FRP) were studied. FRP were studied in terms of generation of active oxygen forms by leukocytes – intensity of chemiluminescence basal and intensity of chemiluminescence stimulated, as well as antiperoxide plasma activity and malondialdehyde. Early postoperative complications were analyzed, the number of repeated lifting surgical corrections on the face was studied for 5 years.The role of FRP in the pathogenesis of involuntary changes in the facial skin has been established. The imbalance of FRP was expressed in the intensification of the reactive oxygen species generation and products of lipid peroxidation. This correlated with disorders of cutaneous microcirculation and a decrease in the saturation of the facial tissues with oxygen, manifested by an increasing energy deficit and the severity of involutional skin changes. The obtained data justify the expediency of using pharmacological conditioning with energy correcting antioxidant medicine. Preoperative conditioning allowed to reduce the number of early postlifting complications associated with tissue trophism in a quarter, especially during surface lifting. In addition, in the preconditioning group, the scar was more cosmetic already at the seventh day after the operation. Based on the study of postoperative catamnesis, self-assessment data and laboratory-instrumental methods of skin system examination in people of different ages, it was revealed that while using SMAS-lifting with a three-level endoscopic-assisted lifting of the lower part of the face, the lowest frequency of complications and the best 5-year effectiveness were established. In addition, the role of free radical processes (FRP), which lead to damage to all of its cellular elements during aging, is repeatedly noted , 16, 17.In this connection, a study was carried out to determine the efficacy and safety of lifting operations in women with varying degrees of involuntary changes in the facial skin, including the use of pharmacological conditioning, with the objectification of the role of the latter.2A survey and surgical treatment to eliminate involutional changes in the facial skin of various degrees in 461 women aged 35–75 years were conducted. 41 (8.9%) patients at the time of surgery was younger than 41 years, 226 (49.0%) – aged 41–55 years and 194 (42.1%) – over 55 years. The severity of the involutional changes in the facial skin varied from I to III degree . In 13.2% of cases, I degree of involutional changes in facial skin was registered, 47.9% – grade II and 38.9% – grade III.6 white blood cells. The marker of lipid peroxidation – malondialdehyde (MDA), as well as the antiperoxide activity of plasma (APA) – the ratio of spontaneous chemioluminescence of secondary plasma to hydrogen peroxide induced chemioluminescence of secondary plasma was studied. FRP was also studied in 21 women aged 20–30 years inclusive, who did not have any involuntary changes in the skin of the face and neck (control group).Instrumental assessment of the skin condition was carried out using laser Doppler flowmetry (LDF) , and with the use of transcutaneous oxygen tension . To assess the state of free radical processes (FRP) in the blood plasma of 84 operated women before the operation, the following laboratory parameters were investigated. Generation of reactive oxygen species (ROC) was determined using a chemilumenometer according to the indices – intensity of chemiluminescence basal (ICb) and intensity of chemiluminescence stimulated by zymosan (ICs), expressing the final result in mV/sec × 10To correct the involutional changes in the facial skin, the patients after the complex clinical, instrumental and laboratory examination performed the following operations of facial and neck skin to correct involutional changes: surface lifting, SMAS-lifting and SMAS-lifting with a three-level endoscopic assist lift of the lower face zone. The standard movement of the facial skin involves the allocation of skin-fat flap within three large zones  with excision of excess skin. In this case, the tightening of the skin is performed through a wide operational access. SMAS-lifting pushes a frame of the classic facelift correction by raising subcutaneous fat and the hypodermic neck muscle with the neck skin as a complex wide musculocutaneous flap. SMAS-lifting with a three-level endoscopic assist lift of the lower face zone is a layer-by-layer tightening of all layers of the skin and muscles through punctures and performing part of the operation by the technique of video endoscopy through small cutaneous accesses. Superficial lifting was performed in 93 (20.2%) cases, including 19 (20.4%) women under 41 years of age, 57 (61.3%) – aged 41–55 years and 17 (18.3%) women over 55 years of age. SMAS-lifting was performed in 226 (49.0%) women, 112 (49.6%) of whom were older than 55 years, 92 (40.7%) – 41–55 years, 22 (9.7%) women on the time of the operation was less than 41 years. Implemented in recent years to the practice of the aesthetic surgery SMAS-lifting with a three-level endoscopic assist lift of the lower zone of the face, was performed in 142 (30.8%) women, including 77 (54.2%) women aged 41–55 years and 65 (45.8%) are over 55 years old.Enrolled in the study, the patients were divided into two comparable groups. With the standard preparation without additional drug correction, 299 women (64.9%) were operated in the preoperative period, they made up a comparison group (group I). The main group (II) consisted of 162 (35.1%) patients who for an average of 10 days (from 7 to 14 days) before the surgery was prescribed therapeutic pre-operative conditioning, i.e. pharmacological correction of pathophysiological components of involutional skin changes, which included the effect on tissue metabolism disorders by stimulants of aerobic and anaerobic glycolysis and tissue perfusion. In some patients, this therapy was carried out not only in the pre- and early postoperative period, but in a number of cases, based on the clinical and laboratory examination, was extended to 6 months after discharge. An antioxidant and energy corrector Cytoflavin (succinic acid + inosine (riboxin) + nicotinamide + riboflavin sodium phosphate (riboflavin)) was administered to 86 women (54.9%) in the main group II at a dose of 1–2 tablets (425 mg) × 2 times a day. In addition, antioxidants Actovegin  at a dose of 200 mg × 3 times a day, Ethylmethylhydroxypyridine succinate  in a dose of 125 mg 3 times a day, Meldonium  in a dose of 300 mg × 2 times a day. In addition, Pentoxifylline was administered to 31 patients (19.1%) at a dose of 100 mg × 3 times a day, Vinpocetine  at a dose of 10 mg × 3 times a day as correctors for microcirculatory blood flow. 58 (35.8%) patients received two of the above mentioned medicines, more often sequentially. The most frequently were used combinations with Cytoflavin (n = 27), among which Cytoflavin and Pentoxifylline were used more often (n = 9). Groups I and II were comparable in age and surgical correction methods .Table 1CTo evaluate the efficacy and safety of operations, early postoperative complications recorded within 7 days after surgery were analyzed, and long-term efficacy results were studied in 5 years after the lifting operation, mainly, the number of repeated lifting surgical corrections on the face was studied for 5 years. Long-term results could be traced in 245 (53.2%) – , in group II n = 97 (59.9%)).Statistical processing of data was carried out using the software SPSS 17.0 with the use of parametric and nonparametric criteria for assessing statistical significance. Differences were considered significant at p < 0.05. Descriptive statistics of qualitative parameters are presented in the form of frequencies , quantitative – median (Me), lower (25%) and upper (75%) quartile in cases where the parameter had a distribution function far from normal. To compare the two independent nonparametric samples, the Mann-Whitney test was used, for a multiple comparison, the Kruskal-Wallis test. Qualitative variables were compared using the χ2 test . The correlation analysis was performed by the Pearson method.3The results of the FRP study objectified their role in the development of involuntary age-related changes in the facial skin. At the first stage of the study, a comparative analysis of various parameters of FRP was performed in operated patients with the same parameters of women in the control group who did not have any involuntary changes in the skin of the face and neck. Significant differences in the parameters of ICb and ICs were established. Thus, the ICb indicator in the control group was, on average, 1.96 times higher than before the operation in patients with involuntary skin changes of varying degrees (p < 0.05). The ICs, on the contrary, in the operated patients was 1.95 times higher than in the control group (p < 0.05). Despite the fact that the level of APA and MDA were characterized by a tendency to increase in comparison with control, these indicators were statistically comparable in both groups .Table 2PThe next stage of the study was a comparative analysis of the FRP indices in women at various degrees of involuntary changes in the facial skin system . A statiChanges in the oxygen phase of the FRP in the form of a decrease in ICb and the growth of ICs caused changes in lipid markers in the blood of women with severe involuntary skin changes. The APA index was characterized by a tendency to increase as the involuntary changes in the skin system progressed. The difference in the APA index between groups with I and III degrees was 1.15 times (p > 0.05). The MDA in women increased in proportion to the degree of involuntary processes and averaged 2.67; 2.81; 3.24 μmol/l for I, II, III degrees of involuntary skin changes, respectively. And in patients with grade III MDA was significantly 1.21 times higher than at grade I (p < 0.05). Significant differences in MDA in patients with I and II degrees, as well as II and III degrees of involuntary changes in the skin were not established.2 in women with I degree were on average 1.38 times higher than in patients with grade III (p < 0.05) , TcpO2 – 54 mm Hg .According to laser Doppler flowmetry (LDF) it was established that the microcirculation of the facial skin decreased significantly as the degree of involutive skin processes increased. The mean total LDF values  in women with the first degree of involuntary changes in facial skin were 1.20 times higher than in patients with grade III (p < 0.05). The indicators of transcutaneous oximetry also decreased as the degree of involuntary changes in the facial skin increased. TcpO < 0.05) . It is iA direct correlation relationship between LDF and ICb  was established, and LDF-inverse correlation with the ICs  was found.The obtained data made it possible to clarify the role of FRP imbalance in pathophysiological mechanisms of aging of the skin system. Imbalance FRP, coupled with tissue hypoxia and a decrease in tissue blood flow, explains the advisability of early energy-based antioxidant pharmacological preconditioning. Therefore, the next stage of the study is devoted to assessing the safety and effectiveness of ongoing operations to eliminate involuntary skin changes, as well as assessing the impact of energy-saving therapy.The total number of early postoperative complications was 37 (8.0%). After the superficial lifting of the cases of early postoperative complications, there were 10 (10.8%), after SMAS-lifting – 25 (11.1%), after SMAS-lifting with three-level endoscopic lifting of the lower zone of the face – 3 cases (2.1%). This speaks in favor of performing SMAS-lifting with a three-level endoscopic lifting of the lower zone to correct involute changes in the facial skin.In the main group of patients receiving energy-corrective therapy, the total number of complications was 11 (6.8%), in the comparison group – 26 (8.7%), which is 1.28 times bigger (p < 0.05). The obtained data indicate that preoperative conditioning allows to reduce the number of early postlifting complications in a quarter. This was best manifested in the course of surface lifting . The least early postoperative complications were after SMAS-lifting with a three-level endoscopic of the lower zone of the face (3.4% in the comparison group and 0% in the main group). Analysis of early postoperative complications in patients of both groups is presented in The most common complication after the lifting operation was a subcutaneous hematoma, diagnosed within the first 24 hours after surgery. An unreliable increase in the number of hematomas with open SMAS-lifting in the group of preoperative conditioning is explained by an active pharmacorrection that stimulated tissue blood flow (p > 0.05). The use of an auxiliary endoscopic technique allowed to completely avoid this type of complications. In none of the cases hematoma increased and did not require re-examination of the postoperative wound with the aim of definitively stopping the bleeding. With the development of hematomas, it was emptied through the hole between the stitches of the cutaneous suture, prescribed hemostatic medication and physiotherapeutic procedures were prescribed from 3 days postoperatively.The frequency of paresis of the mimic muscles, resulting from the direct intersection of branches of the facial nerve or compression by retention suture and with deep anesthesia, was insignificant (0.9%) and did not differ statistically significantly in the groups analyzed. It should be noted that 2 patients out of 4 who developed this complication already had a history of surgery to eliminate involutional changes in the facial skin. Nerve conduction disorders were restored in the period of about 2 weeks, patients were prescribed physiotherapeutic procedures .Marginal cutaneous necrosis along the suture line was observed in all operations with standard preoperative preparation and was completely absent in the preoperative conditioning group. Their frequency was 1.7%, with the majority of complications of this type (3.6%) detected during surface lifting, and with SMAS-lifting, the frequency of such complications was 1.2%. These complications were associated with excessive tension of the skin flap in conditions of impaired tissue trophism. In the SMAS-lifting group with pharmacotherapy this complication was not revealed due to controlled skin tension and better blood supply to the SMAS flap. With the development of this complication, energy-correcting pharmacotherapy and physiotherapy were applied from 1 day postoperative period to soften the necrosis zone and more quickly wound healing.Hair thinning and partial hair loss was observed in 7 cases, all of which occurred in patients without preoperative conditioning. This complication is a consequence of the disturbance of trophic hair follicles in the frontal-parietal and occipital areas, so stimulation of tissue blood flow and metabolic processes allowed them to be prevented.Thus, a comparative assessment of early postoperative complications frequency has convincingly shown that preoperative conditioning reduces the number of complications associated with trophic tissue disorders.Assessment of the scar status in 7 days after the lifting operation established that the postoperative scar was more cosmetic in the pharmacological preconditioning group .The positive results obtained during preoperative conditioning convinced us and our patients in the advisability of continuing this approach to the correction of tissue disorders that promote the inhibition of the progression of involutional skin changes, including in the postoperative period. The next stage of our work was a long-term evaluation (after 5 years) of various surgical interventions results.Evaluation of repeated operations to eliminate involuntary changes in skin of the face in 5 years after discharge showed that during the indicated period, there were 8.2% of cases (20 of 245 women who were observed for 5 years). 5 years ago, these patients underwent various types of surgical anti-aging interventions. 16 of them were after surface lifting, 3 – after SMAS-lifting, 1 – after SMAS-lifting with a three-level endoscopic assist lift of the lower part of the face. In the standard treatment group, there were 15 (10.1% of 148 women), in the conditioning group – 5 (5.2% of 97). All these patients were over 50 years old.4The results of the study demonstrated the role of FRP imbalance in the pathophysiology of the skin system aging. Thus, the indicator of ICb, characterizing the level of intracellular FRP with which the leukocyte reacts to even the minimal oxygen deficiency that develops in the tissues, which provokes a decrease in the tissue renovation processes, normally is high and, with a favorable course of local metabolic reactions, remains so. If this increase is sufficient to solve the anti-inflammatory and antigenerative problems of aging skin, then the body cope with involuntary changes on its own. If there is not enough energy for the cellular elements, then the decrease in ICb is a marker of disorganization and development of an interstitial metabolic processes imbalance. This provokes a slow increase in dismetabolic processes, which are realized by involuntary skin changes especially in patients older than 50 years. The indicator of ICs reflecting the potential ability of the body to generate cytokines in response to the pathological process associated with tissue hypoxia, inflammation and ischemia, on the contrary, increases in proportion to the degree and severity of the involution processes of the facial skin system. As a result of these changes, the APA index, reflecting the level of response of the body's antioxidant systems, prevents the build-up of the damaging effect of oxidative stress, and the MDA index, a secondary product of free radical lipid peroxidation, reflecting the activity of the lipid cascade of oxidative stress in aging women.2 and LDF values correlating with the FRP decrease as the degree of the involutive processes of the skin system increases.The resulting changes in the unbalance of all stages of the FRP with the hyperactive production of reactive oxygen species and the growth of lipid peroxidation products in proportion to the degree of involutionally altered tissues are explained by the presence in women of older age who have a third degree of involuntary changes in the facial skin system, tissue hypoxia, and a decrease in tissue blood flow. These effects were indicated by instrumental methods. In the course of the study based on laser dopplerography and transcutaneous oxygen tension in women, a cellular energy deficit was established due to a decrease in blood flow and transcutaneous oxygen level. The TcpOThus, imbalance of FRP, coupled with tissue hypoxia and lowering of tissue blood flow, explains the expediency of early energy-correlating antioxidant preconditioning.Pharmacological preconditioning positively affected the results of lifting operations effectiveness. Thanks to pharmacological preoperative conditioning, it was possible to reduce the share of early postoperative complications from 8.7% to 6.8%, and the state of postoperative scars was improved. In addition, the group of energy correction noted a tendency to reduce the number of repeated operations to eliminate involuntary changes in the facial skin for 5 years, which is another important argument in favor of the pharmacological conditioning of various lifting operations.Regarding the type of lifting operations, the advantage of SMAS-lifting with a three-level endoscopic-assisted lifting of the lower part of the face was demonstrated over the surface lifting and standard SMAS-lifting.The results of the study can underlie the development of objective markers for predicting the effectiveness of surgical interventions performed to correct involuntary changes in the skin system.5Based on the data presented, the following conclusions can be drawn.With age, the FRP imbalance grows, which is reflected in the reliable regression of the ICb on the background of the ICs and MDA indicators progression, which correlates with skin microcirculation disorders, manifested by the increasing energy deficit and the severity of involutional skin changes. This justifies the advisability of using conditioning by energy-correcting means . Preoperative pharmacological conditioning allows to reduce the number of early postlifting complications associated with tissue trophism, especially during surface lifting in a quarter.Based on the study of postoperative catamnesis, self-assessment data and laboratory-instrumental methods of skin system examination in people of different ages, it was revealed that when using SMAS-lifting with a three-level endoscopic-assisted lifting of the lower part of the face, the lowest incidence of complications and the best 5-year effectiveness were established.Natalia E. Manturova: Performed the experiments; Analyzed and interpreted the data.Victor A. Stupin: Conceived and designed the experiments; Performed the experiments; Wrote the paper.Galina O. Smirnova: Performed the experiments.Ekaterina V. Silina: Analyzed and interpreted the data; Wrote the paper.This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.The authors declare no conflict of interest.No additional information is available for this paper.


Underground ant nests are typically made of soil and rubble mixed with dead plant bodies, ant secretions, and other organic substances. The clay content is high, and the natural clay materials show pozzolanic activity after calcination. In this study, the underground ant nest materials of Iridomyrmex anceps, which is a common ant in the Shanghai area, are calcined and ground, and the material properties of calcined ant nest clay powder (CANCP) are characterized from six aspects: chemical composition, particle morphology, specific gravity, specific surface area, particle size distribution and pozzolanic activity index. The pozzolanic activity of CANCP is evaluated by the strength contribution rate of pozzolanic activity, revealing that CANCP is beneficial to the strength of the mortar system from an early age. The influence of CANCP on the compressive strength of concrete is analyzed using three aspects, namely, content, curing age and calcination temperature, and it is found that the three aspects of CANCP have a strong influence on the compressive strength of concrete.  Ants are excellent architects in the animal world; their nests contain unique structures that feature excellent heat preservation, moisture retention and ventilation function. However, ants have strict demands on the building materials of nests, such as the soil particle size, weight, luster and color. Underground ant nests are typically made of soil and rubble mixed with dead plant bodies, ant secretions and other organic substances, and the content of clay is high. The clay of underground ant nests is composed of earth particles cemented together to form a hard brick-like material. Natural clays typically contain a mixture of clay minerals associated with non-clay minerals. Most natural pozzolans develop their activity from clay minerals such as kaolinite, montmorillonite, and illite. Each type of clay has an optimum calcination temperature range that causes the breakdown of the crystalline structure of the clay and the formation of amorphous silica and alumina . Some po+, Na+, Ca2+, and Mg2+ ions in anthills [2 production [Ants change the physical characteristics of the soil through nesting activities , which canthills  and alteanthills . Throughanthills . Such acanthills . Ant actoduction  and soiloduction . Throughoduction . Thus, rIridomyrmex anceps belongs to the Iridomyrmex category and is distributed across China. Ant nests are underground, and anthills consists of soil particles, the Pinus massoniana male flower, grass, and frass. Anthills are packed into a grave shape, spherical shape, or irregular shape. In this study, the underground nests of Iridomyrmex anceps were sampled from three locations. 2O3 at high temperature under aerobic conditions. The ant nest soil quality at 600 °C and 800 °C after calcination led to masses of 39.25 kg and 38.74 kg and a loss on ignition of 21.5% and 22.5%, respectively. The optimum calcination temperature and time of clay minerals depends on the types of clay minerals, and clay can exhibit potential pozzolanic properties when treated under appropriate calcination temperatures and times. Clay has the greatest activity when it is calcined at 600–800 °C . Thus, 62, Al2O3 and Fe2O3 in 800 °C CANCP and 600 °C CANCP reached 88.76% and 83.37%, respectively, both greater than the 70% specified in the ASTM standard for concrete mineral admixtures [An SM-500 ball crusher was used for milling of the ant nest soil for 60 min after calcination. The chemical composition of CANCP was analyzed using an X-ray fluorescence spectrometer. The total content of SiOmixtures . The resmixtures ,28,29,302/kg. After two tests, the margin of 45 μm square hole sieves was measured as 16.25% and 16.58%, close to the 12% requirement of first-grade fly ash . The speThe particle size distribution of CANCP was determined using a Winner laser particle size analyzer. The results are shown in The pozzolanic activity index of CANCP of 800 °C calcination was evaluated using two methods: the lime absorption method (direct) and the strength index method (indirect).2+ and OH− in solutions of different ages. Lower concentrations of Ca2+ and OH− indicate higher pozzolanic activity [2 at 40 °C). Thus, CANCP material has pozzolanic activity; see The lime absorption method involves mixing a pozzolanic material with a Portland cement slurry or a saturated lime solution, and the activity of pozzolanic material is quantitatively evaluated by measuring the concentrations of residual Caactivity . The actactivity , metakaoactivity , and claactivity  has prevactivity , and theThe strength index method compares the 28 days compressive strength of the contrast mortar of a certain mineral admixture with an equal mass of cement to that of a reference mortar, and the ratio of these two compressive strengths is defined as the activity index of the composite mineral admixture. Among all mineral admixtures, fly ash is the most commonly used and systematically characterized, and recycled powder can be used to grind waste sintered clay brick to a certain fineness, similar to CANCP; fly ash can also be treated through clay calcination and grinding processes. A comparison of the two types of materials would be meaningful; thus, according to GB/T 18736-2002 [PO 42.5 ordinary Portland cement conforming to GB175-2007  was used3, and the average particle size is 16.14 μm.Recycled powder in this study was prepared by smashing, grinding, drying and grading abandoned clay bricks and cement solids. The chemical composition and physical and mechanical properties are listed in The standard sand was ISO679 standard sand. Milled standard sand was obtained by ball milling of the ISO standard sand for 2 h with a SM-500 ball mill, and the sieving test was performed using a FSY-150E cement fineness negative-pressure sieve analyzer. The margin of a 45 μm square hole sieve was 17.55%, the fineness control requirements are close to that of CANCP, and the average size of the ground standard sand was 23.29 μm. The particle size distributions of CANCP, fly ash, recycled powder, and milled standard sand are plotted in Specimens for strength index tests were prepared following GB/T17671-1999 . The cemThe mass mix ratio of reference mortar CT was one part cement, three parts standard sand and half-part water. The reference mortar SS used standard sand instead of 30% quality cement, and the milled standard sand mortar GSS used milled standard sand instead of 30% quality cement. The replacement amount of other pozzolanic ash materials was 30%. The mix design was modified as shown in The CANCP mortar and contrast mortar of each group were cured for 3 days, 7 days, 28 days and 90 days to test their flexural strength and compressive strength following GB/T17671-1999 . FlexuraThe test results are shown in The reference mortar SS uses standard sand instead of cement of the same quality because the standard sand has no pozzolanic activity and because the filling action is weak; thus, the amount of cement decreases. This condition directly results in decreased compressive strength in the mortar, and thus the compressive strength is lower than that of the other mortar after 3 days. The mortar GSS uses milled standard sand instead of cement of the same quality. Milled standard sand also has no pozzolanic activity, but its compressive strength is higher than that of the reference mortar (SS); thus, the micro-filling effect of milled standard sand plays an active role. The compressive strength of CANCP mortar begins to exceed mortar GSS at 7 days, as shown in The activity index of CANCP, fly ash and recycled powder was 76.3, 71.9 and 71.3, respectively, and the activity index of CANCP was larger than that of fly ash and recycled powder and greater than the value of 65 specified in the GB/T2847-2005 standard . These rThe pozzolanic activity index obtained from the compressive strength ratio reflects only whether the admixture has pozzolanic activity; the index does not reflect the extent of pozzolanic activity of the admixture. Pu Xincheng  introducraR, i.e., the strength contribution of unit cement to concrete, is defined as follows:(1) The concrete compressive strength ratio of the mineral admixture raR is the specific strength of concrete containing an admixture (MPa), aR is the absolute value of the strength of concrete containing an admixture (MPa), and q is the percentage of cement content in the concrete cementitious material.In this expression, rrR is defined as follows:(2) The specific strength of reference concrete without mineral admixture rrR is the specific strength of concrete (MPa); aR is the absolute value of the strength of concrete.In the expression: rrR and raR is the specific strength of the pozzolanic effect contribution:(3) The difference between rpR reflects the contribution of the pozzolanic effect of mineral admixtures to the strength of the entire system. A negative value shows that mineral admixtures reduce the strength.hP is defined as follows:(4) The strength contribution rate of cement hydration reaction pP is defined as follows:The strength contribution rate of the pozzolanic effect The pozzolanic activity of CANCP, standard sand, milled standard sand, fly ash, and recycled powder was evaluated using this method. The results are shown in The strength contribution rate of the pozzolanic effect of mortar SS was negative for all ages, and the standard sand had no pozzolanic activity. Thus, standard sand instead of equal-quality cement reduces the strength of cement mortar. The 3 days strength contribution rate of the pozzolanic effect of mortar GSS is 11.73 because it has no pozzolanic activity. For intuitive comparison, the pozzolanic effect strength contribution rate is used to describe its strength in cement paste, and the strength of the pozzolanic effect at this time is contributed by the filling effect of the milled standard sand. The strength contribution rate of the pozzolanic effect of mortar GSS is zero or negative with increasing age, indicating that when milled standard sand is replaced by equal-quality cement, the strength of the cement mortar can decrease, and the contribution of the filling effect of milled standard sand to the strength of the cement mortar appears primarily at early ages. The strength contribution rate of the pozzolanic effect of mortar FA increases with age, and the 3 days strength contribution rate of the pozzolanic effect of mortar FA is negative. This result shows that fly ash has an adverse effect on the early strength of the complete mortar system. The strength contribution rate of the pozzolanic effect is positive starting from the age of 7 days, and the fly ash begins to have a beneficial effect on the strength of the entire mortar system; the 90 days strength contribution rate of the pozzolanic effect of mortar FA is 18.96. The strength contribution rate of the pozzolanic effect of the recycled powder RP is positive at all ages, and the 3 days strength contribution rate of pozzolanic effect is as high as 11.27. Thus, the beneficial influence of recycled powder on the entire mortar system is reflected primarily in the early strength, and the 90 days strength contribution rate of pozzolanic effect is 11.93, with a long-term pozzolanic effect that is less than that of fly ash. The strength contribution rate of the pozzolanic effect of mortar CAP increases with age and is positive. CANCP begins to show a favorable effect on the strength of the mortar system from an early age, and the 90 days strength contribution rate of the pozzolanic effect of mortar CAP is 13.91. The long-term pozzolanic effect of CANCP is larger than that of recycled powder but smaller than that of fly ash.PO 42.5 ordinary Portland cement conforming to GB175-2007  was usedA cubic specimen measuring 100 mm × 100 mm × 100 mm was used to study the compressive strength of concrete following GB/T 50081-2002 . The mol3, the ratio of water to binder was 0.35, and the sand content was 42%. The CANCP with 800 °C calcination was used to replace cement in proportions of 5%, 10%, 15%, 20% and 30%, and the CANCP with 600 °C calcination was used to replace cement in proportions of 10% to study the effect on concrete properties. By adjusting the dosage of water-reducing agent, concrete slump was controlled near 200 mm. The mix proportion and concrete slump are shown in In this experiment, CT was the reference concrete, i.e., ordinary concrete, and a standard mix proportion of design strength of C50 was selected. The calculated mix proportions for the ordinary concrete CT were (cement: water: sand: stone = 486:170:741:1023). For the other six sets of concrete, the total amount of cementitious material was 486 kg/mThe compressive strength of concrete was tested following GB/T 50081-2002 . The tesFor a more intuitive observation and analysis of test results, the ratio of the compressive strength of concrete with varying CANCP content to the compressive strength of reference concrete was used as the relative compressive strength of CANCP concrete. The relationship between the compressive strength of concrete and the CANCP content is shown in The content of CANCP has a strong influence on the compressive strength of concrete. With increasing CANCP content, the cubic compressive strength of concrete first increases and then decreases. Each curve has a peak value, and the compressive strength of the concrete containing 10% CANCP is the largest. The compressive strength for curing times of 3 days, 7 days, 14 days, and 28 days increases by 20.8%, 15.5%, 18.9%, and 18%, respectively, and the early strength increases quickly. When the CANCP content is 20%, the compressive strength of concrete is essentially identical to that of ordinary concrete CT without CANCP. When the CANCP content is more than 20%, the compressive strength of concrete begins to decrease, and the compressive strength for 3 days, 7 days, 14 days, and 28 days curing is reduced by 3.2%, 1.6%, 15.8%, and 15.4%, respectively. The early strength decreases less. Adding CANCP to concrete can improve the strength of concrete, but the content should be less than 20%. The optimum content in this experiment is 10% of the cementitious materials.The development curves for the compressive strength of concrete containing varying CANCP content with age are shown in The compressive strength of concrete containing various CANCP content increases with age. The development of early strength is faster, and the 3 days compressive strength reaches the 28 days strength of 60%, the 14 days compressive strength reaches the 28 days strength of 85%, and the compressive strength between 14 days and 28 days of curing is smaller; the 90 days compressive strength is more than 1.05 times the strength at 28 days. To characterize the changes in the compressive strength of CANCP concrete with age, the relative compressive strength of CANCP concrete at different ages was determined by the ratio of the strength at each age to the strength at 28 days, as shown in cu(t)/fcu(28)) was defined as the age coefficient of concrete (Y). Using the mathematical model Y = A ln (T) + B, where A and B are constants, regression analysis was performed on the relative compressive strength and age of concrete with CANCP content of 5%, 10%, 15%, 20%, and 30%, as shown in The ratio of the compressive strength of CANCP concrete at a certain age to the 28 days compressive strength 2 crystallizes as plates with a large size, small specific surface area, low surface energy, weak interfacial bonding, and a simple orientation arrangement on the surface of the aggregate. Ca(OH)2 acts as an isolation effect between the C-S-H gel and the aggregate and plays a negative role in interfacial adhesion. To increase the strength of concrete, the amount of C-S-H gel should be increased, and the amount of Ca(OH)2 should be reduced [The action mechanism of CANCP in concrete can be explained by the three microstructural phases of concrete, which are hydrated cement paste, aggregate, and the interfacial transition zone between cement paste and aggregate. The influence of the interfacial transition zone on the mechanical properties of concrete is much greater than that of other factors . Interfa reduced . Figure 2O3 and SiO2 formed by the removal of hydroxyl groups can undergo a second hydration reaction with the cement hydration product Ca(OH)2, and this reaction, called the pozzolanic reaction, can generate C-S-H gel. During the pozzolanic reaction, Ca(OH)2 in the hydrated cement paste is consumed, and the amount of C-S-H gel increases. CANCP can also react with the hydration product C-S-H gel in the hydrated cement paste to create additional C-S-H called the pozzolanic C-S-H gel. The composition and properties of pozzolanic C-S-H gel and traditional C-S-H gel are different; the latter is relatively stable after polymerization with OH- and Al2+ and can improve the performance of the traditional C-S-H gel to improve the performance of cement mortar, therefore improving the compressive strength of concrete. In CANCP has strong pozzolanic activity. The amorphous Al2 exists in the interface area of concrete, which makes the interface a weak area. CANCP has a large specific surface area and a large surface energy and can rapidly react with Ca(OH)2 for secondary hydration reactions, reducing the content of Ca(OH)2 in the interface region, also decreasing the crystal size of Ca(OH)2 [2 is found in the hydrated cement paste of the ordinary concrete, but Ca(OH)2 is not found in the cement hydration paste of concrete containing 10% CANCP. CANCP can react with Ca(OH)2 for secondary hydration reactions and can consume the content of Ca(OH)2 in the interface region. The product of reactions between CANCP and concrete can improve the interface structure between cement paste and aggregate. A large amount of Ca(OH) Ca(OH)2 . TherefoThe average particle size of CANCP is 23.35 μm, making it a relatively fine powder particle. Concrete is a granular accumulation system with continuous gradation, and the voids of each aggregate are filled with graded particles smaller than the voids. CANCP particles fill a wide range and can fill the fine pores in hardened cement paste, reducing the porosity of the paste. However, hydration reactions can produce hydrated calcium silicate and calcium sulphoaluminate hydrate with the filling effect and can optimize the internal pore structure of concrete, making the hardened cement paste and concrete stronger and denser. The hydration reactions can also strengthen the hardened cement paste and concrete to be more resistant to external deformation. Under low-magnification electron microscopy, the inner holes of the ordinary concrete are more numerous and are larger, and the surface morphology is not smooth or loose. Instead, there are few holes in the concrete containing 10% CANCP, and its surface is flat and dense.2, Al2O3 and Fe2O3 for 800 °C CANCP and 600 °C CANCP reached 88.76% and 83.37%, respectively, which are both greater than the 70% specified in the ASTM standard.The results of chemical composition analysis indicate that the total contents of SiOIt was shown via two methods (the lime absorption method and the strength index method) that CANCP has pozzolanic activity.The strength contribution rate of the pozzolanic effect of mortar CANCP is positive and increases with age. CANCP has a favorable effect on the strength of the mortar system from an early age.The compressive strength of concrete is maximized at 10% CANCP, and the early strength increases quickly. The compressive strength of concrete containing 20% CANCP is similar to that of the reference concrete without CANCP. When the content of CANCP is above 20%, the compressive strength of concrete begins to decrease, and the early strength decreases less.The compressive strength of concrete with various CANCP content increases with age, and early strength develops faster. Increased strength is generally consistent with age when the CANCP content is not more than 15%.The compressive strength of concrete containing CANCP with 800 °C calcination is higher than with calcination at 600 °C. CANCP with 800 °C calcination thus shows superior pozzolanic activity.CANCP can improve the strength of mortar and concrete mainly because it can accelerate the hydration of cement and exhibits the pozzolanic and filling effects. Accelerating cement hydration and the pozzolanic effect is important for improving the strength of mortar and concrete, to which the filling effect also contributes in a secondary manner.The results of experimental studies on calcined underground ant nest materials were presented, and the following conclusions were drawn:


Erythrocytes and breast milk DHA concentration was significantly reduced during lactation compared to pregnancy, a pattern not observed for AA. We concluded that is necessary to increase the intake of n-3 PUFA during pregnancy and lactation by improving the quality of consumed foods with particular emphasis on its DHA content.Maternal diet during pregnancy is relevant for fatty acid supply during fetal life and lactation. Arachidonic (AA) and docosahexaenoic (DHA) acids are also relevant for the normal growth and development of brain and visual system. AA and DHA provided by the mother to the fetus and infant are directly associated with maternal dietary intake and body stores. Our aim was to evaluate the impact of maternal diet, specially referring to the quality of fatty acid intake, in a sample of Chilean women during last stage of pregnancy and across the lactation period. Fifty healthy pregnant women (age range 20–33 years) were studied from the 6th month of pregnancy and followed until 6th month of lactation period. Diet characteristics were evaluated through food frequency questionnaires. Fatty acids composition of erythrocyte phospholipids and breast milk samples was assessed by gas-liquid chromatography. Overall, women had high saturated fatty acids intake with sufficient intake of mono- and polyunsaturated fatty acids (PUFA). Diet was high in  Humans n-6 fatty acids, the synthesis of AA from LA when this fatty acid is highly consumed is more efficient than the synthesis of DHA from ALA [Hepatic synthesis of AA and DHA is a fundamental metabolic process necessary to ensure the constant supply of these LCPUFA to other tissues . Synthesfrom ALA .n-6 and n-3 LCPUFA availability.Several studies have established the relevance of the fatty acid composition of breast milk and its direct association with the diet of the mother during pregnancy and lactation ,14,15. Tn = 50) who attended the Obstetrical and Gynecology Health Service of the Clinical Hospital, University of Chile, Santiago, Chile were included in the study. Inclusion criteria were women between 20 and 33 years; gestational age at least 22 and up to 25 weeks according to the date of the last menstrual period and confirmed by ultrasound; and history of successful lactation. Exclusion criteria were women with history of drug or alcohol consumption; with current consumption of n-6 and/or n-3 LCPUFA supplements; who were underweight (as defined by the Chilean chart for pregnant women [Pregnant women (nt women ); who hant women . All womAt the time of recruitment, all women who fulfilled the inclusion criteria were given general information about the study, and a dietitian explained the objectives and main characteristics of the research. The protocol was reviewed and approved by the Institutional Review Board of the Faculty of Medicine, University of Chile (Protocol #073-2011), and by the Ethics Committee of the Clinical Hospital, University of Chile (Protocol #507/11). All information regarding the study was given to each participant who voluntarily agreed to participate and signed the informed consent.2), which was then used to establish the maternal nutritional status according to gestational week following the Chilean reference [Participants were subject to a clinical evaluation when incorporated into the study. A physician and a nurse assessed each woman regarding her health by following the standard clinical approach for pregnant women. Anthropometric data of weight (kg) and height (m) were assessed to determine body-mass index , to calculate the daily intake of energy and nutrients. Nutritional composition of foods was obtained using a database from the USDA National Nutrient Database for Standard Reference, which also incorporated information from locally generated nutrient composition data.All women were interviewed by trained dietitians at the enrollment of the study and asked to report all groups of foods consumed at the first week after delivery and during the six-month of lactation, using a food frequency questionnaire. In addition to this questionnaire and in order to improve the estimation of eaten foods, dietitians used a photographic atlas of commonly consumed foods in Chile , which ig for 10 min at 20 °C) and then frozen at −80 °C until further analysis. Breast milk was extracted by the mothers themselves after the infant had been fed for at least 2 min and was collected in plastic vials. Breast milk samples (5 mL) were collected monthly from the 1st until the 6th month of lactation. Once collected, the samples were immediately frozen at −80 °C until further analysis. Details of the analysis of fatty acids of erythrocyte phospholipids and breast milk samples were previously described by Valenzuela et al. [Blood samples were obtained at the enrollment, immediately after the delivery and at the 1st and the 6th month after lactation. The samples were immediately centrifuged to obtain the erythrocyte fraction . p < 0.05) than delivery compared with other times evaluated. At the beginning of the study, 4.4% were underweight. At the end of the study, 46.7% of women were overweight and 16.1% obese; therefore, 62.8% exhibited overnutrition, and no underweight was observed. The 45% of deliveries were after cesarean, condition that may modify the milk production in amount and nutritional quality . At 6th month of lactation, infant presented a normal increment of weight and height. An important aspect is the increase in weight of the women from the 6th month of pregnancy until the delivery (12.2 kg on average), along with the weight of infant at birth, which on average was 4.25 kg.p < 0.05) at the 1st and 6th month of lactation when compared to the 6th month of pregnancy. In addition, consumption of dairy, meat, and eggs was reduced (p < 0.05) at 6th month of lactation. Consumption of high-fat foods was not significantly modified during the study. A reduction (p < 0.05) of the ingestion of fish and seafood (39.3% at the 1st month of lactation and 54% at the 6th month of lactation) compared to the 6th month of pregnancy was observed.n-6 fatty acids, LA, and AA, together with an adequate intake of total monounsaturated fatty acid (MUFA) and total polyunsaturated fatty acid (PUFA) and a low intake of total n-3 fatty acids ALA, EPA, and DHA. At the 1st month of lactation a significant reduction of the intake of EPA and DHA  was produced, and at the 6th month this reduction was 50% for both LCPUFA, compared to the values at the 6th month of pregnancy. The rest of the most relevant fatty acids and the n-6/n-3 PUFA ratio were not significantly modified.n-6 LCPUFA when compared to the values for the 6th month of pregnancy and for the 6th month of lactation. However, docosapentaenoic acid  was significantly increased (34.2%) and DHA and total n-3 LCPUFA were significantly reduced for the same period . n-3 LCPUFA, which were significantly reduced from the 4th month of lactation. It is interesting to mention that at the 6th month of lactation the levels of DHA, LCPUFA, and n-3 LCPUFA were even lower (p < 0.05) than the values observed at the 4th month of lactation. In addition, the DHA was reduced by 38.5% at the 4th month of lactation and by 64.1% at the 6th month of lactation, compared to the values obtained at the 1st month of lactation. The reduction of n-3 LCPUFA is reflected in the significant increase of the n-6/n-3 LCPUFA ratio. Data from n-6 PUFA, LA, and AA , which can produce a reduction of the capacity of the mother for transferring DHA to her offspring during pregnancy and breast feeding [A woman’s diet during pregnancy and lactation has a fundamental role in the adequate contribution of macro and micronutrients for her infant during the fetal life and during lactation ,23. The , and AA , and a l and DHA . In this and DHA , added t feeding ,26,27. In-6 and n-3 LCPUFA, but being the diet sufficient in AA, the effect of polymorphism should be more deleterious for the availability of DHA than AA [n-6 to n-3 PUFA can lower the synthesis of n-3 LCPUFA, particularly DHA, because of the competition generated between the respective precursors for the active sites of desaturase enzymes [n-6 fatty acid (such as LA) may decrease the synthesis of DHA from ALA [n-3 LCPUFA (DHA), an aspect that remains to be studied. The synthesis of LCPUFA, as well as the availability of precursors and the activity of Δ-5 and Δ-6 desaturase enzymes, is also dependent on the availability of specific nutrients, such as zinc, magnesium, calcium, vitamin B6, and vitamin C [n-3 LCPUFA in erythrocytes and breast milk, as was observed in this work , starting from the 4th month of lactation  instead of the traditionally consumed oils (soy and sunflower oil) from the 6th month of pregnancy and until the 6th month of lactation, it a significant increase of DHA levels in breast milk was produced, but only until the 3rd month of lactation, without modification of the AA levels during the 6th month of lactation. The same authors reported that AA and DHA in erythrocyte phospholipids were not modified during the dietary intervention [In relation to the Chilean population, Bascuñán et al.  reportedactation . In thisrvention , suggestrvention .n-3 LCPUFA, dietary strategies have been developed to improve the quality of the diet of women during pregnancy and lactation through educational programs focused on promoting consumption of foods that provide DHA  [p < 0.05) observed in erythrocytes and breast milk in women’s sample  ,46,47. H origin) ,47, whic origin) ,49,50. Is sample  may be an-3 fatty acids  and a high intake of n-6 fatty acid (LA and AA). This dietary situation produced a significant reduction of DHA levels in erythrocytes and breast milk. Therefore, it is necessary to promote the consumption of foods that naturally contain DHA or are fortified with n-3 LCPUFA. Another alternative is direct supplementation with DHA during pregnancy and lactation through products now widely available (fish oil or krill oil capsules or microcapsules). This study shows that Chilean women during pregnancy and lactation have a low intake of foods that are natural sources of