The high value use of agricultural and livestock waste resources in the context of a low carbon economy is a challenge that currently plagues many countries. Yak dung, as a waste resource from livestock farming in the plateau, is considered to be a misplaced treasure. In this work, yak dung was processed into yak dung fiber (YDF) and yak dung ash (YDA), respectively, and the microscopic morphology of the YDF and YDA was assessed using scanning electron microscopy (SEM). The elements in the YDA were analyzed by energy dispersive X-ray spectroscopy (EDX). Moreover, cementitious composites were prepared with YDF at 0%, 0.3%, 0.5% and 0.7% and by replacing cement with YDA at 5%, 10% and 15% to assess the workability, mechanical properties and shrinkage properties of cementitious composites containing different YDF types , contents and different YDA contents. The results showed that alkali-treated YDF and YDA contain a large number of honeycomb structure pores, and the strength of cementitious materials with alkali-treated YDF was higher. The addition of YDF had a negative effect on the fluidity and compressive strength of the cementitious material, but the 0.3% YDF was beneficial in increasing its flexural strength. The compressive strength and flexural strength first increased and then decreased with the increase of YDA content. Both YDF and YDA inhibited the shrinkage of the cement paste, and the shrinkage strain of the cement matrix composites containing 0.3% YDF and 10% YDA was reduced by 51.1% compared to the control group. This work is expected to promote the application of yak dung waste in cementitious materials. Control targets ,6. Takinin China . Therefoin China ,9. A comin China ,11. On tin China . Generalin China ,14.2O3, 18~22% Fe2O3 and 58~62% SiO2 [With the increased government investment in infrastructure construction on the Tibetan plateau in China, a large amount of cement is bound to be consumed during the construction process. Furthermore, due to the special climatic environment of the Tibetan plateau, higher requirements are placed on the durability of the cementitious materials . The yak62% SiO2 . It can Some efforts and attempts have been made to maximize the value of cattle manure waste in applications such as wastewater treatment, composting, fermentation, porous activated carbon powder, low-cost insulation, road base soil stabilizer, fiber reinforcement and auxiliary cementitious materials ,24,25,262+Al2O3+Fe2O3 in cattle dung ash reached 52.26% and the compressive strength of concrete decreased gradually with the increase of cattle dung ash admixture, but the 56-d compressive strength of concrete with 5%, 10% and 15% cattle dung ash reached 96%, 95% and 94% of the control group, respectively [Cattle dung ash, obtained by calcining sun-dried cattle dung, has volcanic ash properties and is considered to be an effective alternative to cement as a supplementary cementitious material. As far as the application of cattle dung ash in cementitious materials is concerned, lots of effort has been made by researchers. Sahin et al. studied the chemical properties and pozzolanic effect of cattle waste ash, and the content of SiOectively . Ojedokuectively . Mbereyaectively . Ramachaectively . The aboectively .In summary, there is still very limited research into the use of cattle dung fibers in cementitious materials, and there is no report on the synergism application of cattle dung fiber and cattle dung ash being used as reinforcement materials in cementitious composites. The main objective of this study is to investigate the effect of yak dung fibers (YDF) and yak dung ash (YDA) on the mechanical and shrinkage properties of cement mortar when they act synergistically. For this purpose, the effects of different YDF types , contents  and different YDA contents  on the flowability, compressive and flexural strengths at 3 d, 7 d and 28 days and shrinkage properties of cementitious composites up to 7 d after demolding were evaluated, and the analysis of variance (ANOVA) was also used to statistically analyze all the test results to determine the significance of the effects of YDF type, YDF content, and YDA content on the mechanical and shrinkage properties. Furthermore, the surface morphology of alkali-treated and untreated YDF, YDA and cementitious materials at the curing age of 28 d were analyzed to determine the mechanism of the synergistic effect of YDF and YDA on the physical and mechanical properties and shrinkage properties of cementitious materials. This work is expected to promote the application of yak dung waste in cementitious materials and to improve its crack resistance.The ordinary Portland cement P·Ⅰ 42.5 (OPC), conforming to the Chinese standards, produced by Qufu Zhonglian Cement Co., Ltd, Shandong, China. was used in this study. The chemical composition of cement determined by X-ray fluorescence analysis (XRF) was shown in The yak dung is obtained from the excrement of yaks, which is taken from the grasslands of the Tibetan plateau pastoral areas. When it is obtained, it has been dried in the sunlight in the form of cakes. Here, since yak mainly feed on grass and highland barley straw, their dung contains a lot of straw fibers. Therefore, yak dung is used to make YDF and YDA.The cellulose content determines the mechanical properties of the fiber, and a high cellulose content is beneficial to the tensile strength of the fiber. Li et al. treated cattle dung fibers using 1 mol/L and 3 mol/L NaOH and found that the tensile strength of alkali-treated cattle dung fiber was 89 MPa and 84 MPa, respectively, which increased by 36.9% and 29.2% compared to 65 MPa in the control group . This in2 in YDA, which leads to a decrease in the content of amorphous silicon and reduces its activity. In this study, referring to the optimal calcination condition of highland barley straw ash, the calcination temperature was 600 °C and the calcination time was 2 h [Nitrogen, potassium and calcium are abundant in YDA’s chemical makeup, and the carbon to nitrogen ratio is comparatively high . The yak was 2 h . TherefoIn order to investigate the effect of YDF and YDA on the mechanical properties and shrinkage characteristics of cementitious composites, thirteen cementitious mixes were designed in this paper, and the mix composition is shown in The procedures for the preparation of the YDF cement mortar specimens consisted of the following steps. Firstly, a certain mass of dried YDF was weighed and water was absorbed until saturated. Secondly, the saturated YDF were added to the mixing water (70%) and placed in ultrasound for 3 min to ensure a homogeneous dispersion of the YDF. Thirdly, the mixed fiber solution was added to the cement mortar mixer and slowly added to the cement and mixed for 1 min. Fourthly, the remaining mixing water (30%) and SP were added and mixed for 1 min. Fifthly, ISO standard sand was slowly added and mixed for 2 min. Finally, the freshly mixed cement mortar was filled into the specimen moulds and vibrated concomitantly. And then, each specimen was demolded after being hardened in the laboratory for 24 h. Demolded specimens were placed to a concrete curing room at a temperature of 20 ± 2 °C and a humidity of 97% until the test age.The effect of the addition of YDF and YDA on the physical properties of cement mortars can be determined by monitoring the fluidity of the fresh cement mortar mix. After obtaining a fresh cement mortars mixture, fluidity test was performed to evaluate the workability of the cement mortar specimens according to the Chinese standard GB/T 2419-2005 .According to the Chinese standard JTG 3420-2020 [t is the shrinkage strain of the cement mortar specimen at t moment (μm/m), Δl is the deformation of the specimen at t moment (mm) and l0 is the length of the cement mortar specimen, 160 mm.The curing age of 1d is used as the starting point for measuring mortar shrinkage in this paper. As shown in Microscopic morphology of YDF, YDA and different cement mortar specimens were characterized by scanning electron microscope (SEM) with an accelerating voltage of 5–15 kv, and the specimens needed to be gold sprayed to conduct electricity prior to testing. The elements in the YDA were analyzed by energy dispersive X-ray spectroscopy (EDX).The dispersion of 3 g treated YDF and 3 g untreated YDF in water is given in 2 in YDA is amorphous and has a high activity, which can react with Ca(OH)2 to produce a higher strength low alkalinity hydrated calcium silicate gel [cate gel .The fluidity of cement mortars with different contents of YDF and YDA are given in The effects of pretreated and untreated YDF on the 3 d, 7 d and 28-d compressive strength of cement mortars are shown in It can also be seen from 2 and Al2O3, and the Ca(OH)2 generated by the hydration of the cement further undergo a secondary hydration reaction to form the calcium silicate  hydrate C-S(A)-H gel, which can further reduce the voids and lead to the increased strength performance of cement mortar [t mortar . In addiThe relationship between the YDF content , the YDF type (pretreated and untreated) and the flexural strength of the cement mortar at different curing ages is given in The flexural strength of cementitious mortars at different ages by the coordinated action of YDF and YDA is shown Reference  pointed p-value less than 0.05 classifies a parameter as significant. As can be seen from The statistical significance of the experimental results was quantified at a significance level of 0.05. The measured parameters of cement mortar such as fluidity, 28-d compressive strength, 28 d flexural strength and 156 h shrinkage strain were characterized as dependent factors, whereas YDF type, YDF content and YDA content indicated independent factors. The analysis results are presented in In this study, the YDF obtained by pretreatment of cow dung with 1 mol/L of a NaOH solution and the YDA obtained by calcination of cow dung at 600 °C were used in the preparation of cementitious reinforcement materials. The effects of untreated and pretreated YDF and YDA on the mechanical properties and shrinking properties of cementitious composites were studied. The main conclusions are as follows.(1) YDF treated with the NaOH solution is more evenly dispersed in water, and NaOH can dissolve impurities such as hemicellulose and lignin in YDF, which makes the YDF surface appear hollow and enhances its surface roughness, thus improving the interface adhesion between YDF and cement matrix. 2 of cement in a secondary hydration reaction to produce more C-S(A)-H gels and improve the denseness of cementitious materials.(2) YDA is composed of honeycomb structures with a scale of about 5–10 μm and contains a large number of pores. YDA contains elements such as Si, Al and Ca in the form of oxides in addition to C. It can react with the hydration product Ca(OH)(3) The fluidity of cement mortar decreases with the increase of YDF and YDA content. The compressive strength of cement mortar decreases gradually with the increase of YDF content, but when the content of YDF exceeds 0.3%, the compressive strength of cement mortar decreased significantly. The compressive strength of cement mortars with pretreated YDF is greater than that of cement mortars with untreated YDF for the same YDF content at each age.(4) The flexural strength of cement mortar first increased and then decreased with the increase of pretreated YDF content. When the content of pretreated YDF was 0.3%, the flexural strength reached the maximum. However, the flexural strength of cement mortar gradually decreased with the increase of untreated YDF content.(5) With the increase of YDA content, the compressive strength and flexural strength of cement mortar increased first and then decreased, and when the YDA content was 10%, the compressive strength and flexural strength reached the maximum. When YDF and YDA acted in synergy, the content of YDF was 0.3% and the content of YDA was 10%, and the compressive strength and flexural strength of cement mortar were the largest, which was superior to the physical and mechanical properties of the control group.(6) The incorporation of YDF and YDA was beneficial to inhibit the shrinkage of cementitious materials. When the content of YDF and YDA in cement mortar is 0.3% and 10%, the shrinkage strain of cement mortar was the smallest, which is reduced by 51.1% compared with the control group at 156 h shrinkage age.In general, this paper conducted a preliminary study on the recycling of yak feces and demonstrated that both YDF and YDA can be used as an auxiliary additive material in concrete materials, which is of great significance for improving the recycling rate of yak feces and reducing carbon emissions in the cement manufacturing process. Nevertheless, further research is still needed in terms of the optimal preparation process, practical engineering applications, economic benefits and durability of cementitious mixture of YDF and YDA in the future.


Saccharomyces cerevisiae strain 1026) on the amount of ghrelin-IR cells in the abomasum and intestines of 13-14-week-old calves.The use of antibiotics in animals for disease prevention and productivity has been banned in the European Union since 2006. Possible alternatives can be used prebiotics, probiotics, and synbiotics. These compounds can improve feed digestion and absorption in the gastrointestinal tract with identical nutrient uptake, while imparting the feeling of satiety, which reduces the activity of ghrelin-immunoreactive (IR) cells. The number of studies performed on the activity of ghrelin-IR cells in ruminants is insufficient. In particular, there are few such studies in calves during the transition period from being a relatively monogastric animal to a ruminant. The present study aimed to evaluate the effect of Jerusalem artichoke flour (containing ~50% prebiotic inulin) and a new, commercially unavailable synbiotic   were used. Calves were allocated into three groups: Control group  received the standard diet, prebiotic group  received 12 g of flour of Jerusalem artichoke (Helianthus tuberosus) per head containing 6 g of prebiotic inulin in addition to the standard diet, and synbiotic group  received a synbiotic in addition to the standard diet which consisted of two different products: 12 g of flour of Jerusalem artichoke per head containing 6 g of prebiotic inulin and probiotic 5 g of a yeast S. cerevisiae strain 1026. Feed additives were added to the concentrate once a day for 56 days. On days 1, 28, and 56, the live weight of the calves was determined. On day 56 of the experiment, three calves from each group were slaughtered. Histological samples were collected from the two parts of each calf abomasum: Pars pylorica and pars fundalis and the middle part of the duodenum and jejunum. Immunohistochemical tissue staining methods were used to detect ghrelin-IR cells.Fifteen crossbreed, Holstein Friesian and Red Holstein calves , while the difference between the PreG and SynG was not significant (p=0.700).The live weight of the slaughtered calves on day 56 was 115.3±21.73 kg in CoG, 130.0±17.32 kg in PreG, and 119.0±7.94 kg in SynG. Ghrelin-IR cells were more abundantly localized in the cytoplasm of the abomasum muscle gland cells in S.cerevisiae stain 1026 in calves resulted in a lower number of ghrelin-IR cells in the abomasum, duodenum, and jejunum and, although insignificantly, increased live weight (p=0.491), suggesting that calves in these groups with the same feed intake as the CoG had a better breakdown of nutrients, thus having a longer feeling of satiety.The addition of Jerusalem artichoke flour and its combination with the yeast  The transition from milk feeding to roughage and concentrate feeding in calves’ lives is associated with various physiological and anatomical changes in the digestive tract, which is undergoing rapid microbial and structural modifications. This period causes additional stress in calves and may contribute to the development of various infectious diseases that may adversely affect their growth and development .Today, with the rapid development of dairy farming, there is a growing need for healthier calves, which have better growth rates and are more productive. This is often achieved through the preventive use of antibiotics. However, the use of antibiotics in animals for disease prevention and productivity has been banned in the European Union since January 1, 2006, according to Regulation (EC) No. 1831/2003 of the European Parliament and of the Council [4) production [Saccharomyces cerevisiae are microorganisms that have a broad range of beneficial effects such as regulation of intestinal microbial homeostasis, stabilization of gastrointestinal barrier function [4 gas [Possible alternatives with similar properties are prebiotics, probiotics, and a combination of both synbiotics. The most significant effect of these additives is observed on the gastrointestinal microflora by promoting the growth of beneficial microorganisms. This, in turn, has a positive effect on the whole organism; animals show an increase in live weight, a lower number of pathogenic microorganisms in the digestive tract ,4, and toduction ,11. Inuloduction ,13. Probfunction , and impfunction , resultifunction . Yeast an [4 gas . Synbiotn [4 gas . These fGhrelin is a peptide of 28 amino acids in monogastric animals and 27 amino acids in ruminants , except In ruminants, ghrelin is mainly produced by the endocrine cells of the abomasal mucosa . It has Many studies have been conducted on the activity of ghrelin-IR cells in monogastric animals ,30, but S. cerevisiae strain 1026) on the amount of ghrelin-IR cells in the abomasum and intestines of 13-14-week-old Holstein Friesian and Red Holstein crossbred calves. At the same time, an effort was made to examine how these feed additives affect the live weight of calves and to indicate a possible correlation between live weight and the number of ghrelin-IR cells in the digestive tract of calves.Therefore, the present study was conducted to evaluate the effect of Jerusalem artichoke flour (containing ~50% prebiotic inulin) and a new, commercially unavailable synbiotic . Three calves from each group were slaughtered at the end of the experiment to obtain samples of the gastrointestinal tract for histological examination. Following the ethical requirements to minimize the number of animals used in experiments, we chose to organize as small groups as possible .The study was conducted on a dairy cow farm from December 2017 to February 2018. The farm is located in Saldus district, Jaunlutriņi parish (latitude: N 56.8287° and longitude: A 22.4065°).Bos taurus) crossbreed calves with a mean age of 32±4 days and initial body weight of 72.1±11.34 kg were used in the present study. Throughout the study, the health status of the calves was evaluated by both the persons involved in the study and the farm veterinarian. No prolonged diarrhea, respiratory diseases, or other conditions were observed in the calves that could affect the study and the results obtained. The examination of the calves and the collection of all samples were conducted under the supervision of the farm veterinarian. All calves were housed in groups in a partly closed pen on the farm. After birth, all calves received colostrum, and for the next 5 days, calves received whole milk (3.5 L twice a day) and later the milk replacer in a dosage appropriate to their age and weight. Within the age of 32-64 days, calves received 8 L of milk replacer per day and a pre-starter diet without restriction . Within the age of 64-88 days, calves received approximately 1.5 kg of barley flour and 6 L of milk replacer per day. During the experiment, the calves had free access to hay and water. The chemical composition of the nutrients used in the study is presented in Fifteen clinically healthy randomly selected Holstein Friesian and Red Holstein (Helianthus tuberosus) per head containing 6 g of prebiotic inulin  in addition to the standard diet, and synbiotic group  received a synbiotic in addition to the standard diet which consisted of two different products: 12 g of flour of Jerusalem artichoke per head containing 6 g of prebiotic inulin and probiotic 5 g of a yeast culture based on the S. cerevisiae strain 1026 .The yeast feed additive used in the study is registered for use in the countries of the European Union (EC Regulation No. 1109/2014). However, the synbiotic used in the study is not commercially available and was manufactured for this study. The flour of Jerusalem artichoke and synbiotic were added to the concentrate (pre-starter and later barley flour) once a day in the morning.Calves were allocated into three groups: Control group  received a standard diet, prebiotic group  received 12 g of flour of Jerusalem artichoke (The duration of the experiment was 8 weeks (56 days). On days 1, 28, and 56 of the study, the live weight of the calves was determined by a recognized indirect live weight determining method using a special measuring tape Animeter . Live weight can be determined by measuring the circumference of the chest just behind the elbows and reading the result on a tape measure. This method, which is based on the standard growth curves of cattle, is widely used to determine the live weight on farms .Pars pylorica and pars fundalis, as well as the middle part of the duodenum and the middle part of the jejunum. The obtained samples were rinsed with 0.9% sodium chloride solution and placed in bottles filled with 10% formalin . The tissue samples were fixed in 10% formalin solution for at least 48 h. Immunohistochemical tissue staining methods were used to detect ghrelin-IR cells. The staining of IR cells was performed using the streptavidin-biotin complex . The examined tissue samples were applied to silane-coated slides  and then dried for 12 h at a thermostat setting of 37°C. The samples were then deparaffinized with xylene and dehydrated with a series of ethanol reductions. After dehydration, the samples were placed in a 65°C buffer solution at pH 9.0  and treated twice with a break of 70°C in a microwave at 450 W for 5 min to release epitopes to bind the antigen to the antibody. The samples were then cooled at room temperature (~22°C) and amplified for 5 min with endogenous peroxidase blocking reagent  to block endogenous peroxidase. Rat and mouse polyclonal antibodies  at a dilution of 1:500 was used as primary antibodies. For IR cell and primary antibody responses, the antigen-antibody complex was labeled by application of the secondary antibody for 30 min and then stained by application of the DAB+ complex for 5 min . The tissues were stained with hematoxylin to provide contrast to the sample and to avoid artifacts. The stained samples were incubated in a humid chamber at ~22°C and the samples were rinsed with phosphate buffer .At the end of the experiment, three calves from each group were slaughtered in a certified slaughterhouse following all humane slaughter guidelines. Histological samples were collected from the two parts of each calf abomasum: Histological samples of the pylorus of the dog’s stomach were used as a positive control for ghrelin antibodies. The same samples were used as negative controls, except that they were treated with an antibody diluent instead of the primary antibody (no immunoreaction was observed).2. The samples were examined at 400× with an EVOS M5000 microscope .The quantitative composition of IR cells was evaluated in each sample in 10 fields of vision by determining the mucosal area and the number of positive cells in it by determining the number of IR cells in 1 mmThe assumption of normal data distribution was assessed using the Shapiro-Wilk test and visual inspection of their histograms and normal Q-Q plots. The assumption of homogeneity of variances was tested by Levene’s test. To determine whether there were any statistically significant differences between the three independent groups, we used the Kruskal-Wallis H test with pairwise comparisons using Dunn’s procedure  with a Bpars fundalis and pars pylorica, and to a lesser extent in the duodenum and jejunum. In the area of the fundic glands, as well as in the duodenum and jejunum, ghrelin-IR cells were found mainly at the apical ends of the glandular cells, but in the area of the pyloric glands, these cells were mainly found in paranuclei and also in the cell nuclei. The ghrelin-IR cells in the samples stained brown when stained with DAB+, and the cells themselves were round, oblong, and square in shape. No positive staining results were observed in the negative control samples .Ghrelin is a hormone that plays an important role in the regulation of various physiological processes. It affects the growth and development of the body by promoting the release of growth hormone from the pituitary gland ,21 and, In ruminants, ghrelin is mainly produced in endocrine cells of the abomasal mucosa . In the ad libitum, Group 2 – ad libitum and intravenous ghrelin injection (1 g/kg), Group 3 – fed once per day, and Group 4 – fed twice a day), which lasted for 1 month, it was observed that the number of ghrelin-IR cells in the areas of the cardiac, fundic, and pyloric glands of the abomasum did not differ significantly among groups of sheep with different feeding regimens [S. cerevisiae strain 1026. For example, in the calves of the CoG, the number of ghrelin-IR in the fundic gland zone of the abomasum was Me=12, IQR 10-14, in PreG Me=6, IQR 4-9, but in SynG Me=5, IQR 5-8. A higher number of ghrelin-IR cells in the gastrointestinal tract could indicate a higher amount of ghrelin secretion. Considering that ghrelin is produced in response to hunger and decreases after a meal when the animal experiences satiety [S. cerevisiae to cow diets improved cellulose digestibility, while Samanta et al. [In a study of 2-month-old sheep (n=16) with the same diet but different feeding regime  was lower than that of calves which additionally were supplemented with feed additives (PreG 130.0±17.32 kg and SynG 119.0±7.93 kg), no correlation was found between the number of ghrelin-IR cells in different parts of the digestive tract and the live weight of calves on day 56 of the study .However, to better assess the changes in the amount of ghrelin-IR cells depending on the feed additives, studies with larger groups of calves are required. The amount of ghrelin in the blood plasma should also be determined, which could provide more accurate information on the hormonal regulation of hunger and satiety, as well as information on the effects of ghrelin on animal growth.S. cerevisiae strain 1026 (5 g) in calves resulted in a lower number of ghrelin-IR cells in the abomasum and intestines and, although insignificantly, increased live weight (p=0.491), suggesting that calves in these groups with the same feed intake as the CoG had a better breakdown of nutrients, thus having a longer feeling of satiety. The limitation of this study was the small number of calves. We followed the 3Rs principle – reduce the number of animals used per experiment or study consistent with the scientific aims. This was discussed with the Council for Ethical Treatment of Animals, Latvia University of Life Sciences and Technologies, and it was decided to use only five animals per group and slaughter only three animals per group, as this was estimated to be a sufficient number of animals to meet our research goals. Statistical analysis of the data was performed using methods suitable for a small amount of data.The addition of Jerusalem artichoke flour (12 g) containing 5 g of prebiotic inulin and its combination with the yeast SJ: Collected the samples, performed the clinical examination of calves, evaluated immunohistochemical staining of histological specimens, and drafted and revised the manuscript. AI: Designed the concept for this research and scientific paper. AI*: Collected the samples and performed the clinical examination of calves. MZ: Performed the statistical analysis of all data. LG: Collected the samples and performed the clinical examination of calves. All authors read and approved the final manuscript.


The polarization sensitivity of azopolymers is well known. Therefore, these materials are actively used in many applications of photonics. Recently, the unique possibilities of processing such materials using a structured laser beam were demonstrated, which revealed the key role of the distribution of polarization and the longitudinal component of light in determining the shape of the nano- and microstructures formed on the surfaces of thin azopolymer films. Here, we present numerical and experimental results demonstrating the high polarization sensitivity of thin azopolymer films to the local polarization state of an illuminating structured laser beam consisting of a set of light spots. To form such arrays of spots with a controlled distribution of polarization, different polarization states of laser beams, both homogeneous and locally inhomogeneous, were used. The results obtained show the possibility of implementing a parallel non-uniform patterning of thin azopolymer films depending on the polarization distribution of the illuminating laser beam. We believe that the demonstrated results will not only make it possible to implement the simultaneous detection of local polarization states of complex-shaped light fields but will also be used for the high-performance fabrication of diffractive optical elements and metasurfaces. The possibility of processing materials not with one laser beam but with multiple laser beams has made it possible to increase the processing speed by orders of magnitude ,2,3,4,5.f optical systems with spatial polarization filtering [q-plates/S-waveplates [f optical system, we can use such a polarization filter to transform the linear polarization of each multiplexed laser beam into a linear polarization with the desired polarization direction. Such transformed laser beams can be used for locally variant patterning of polarization-sensitive azopolymers films for the fabrication of various elements of diffractive optics and photonics.We should note that some polarization transformation and generation of multiple laser beams with different polarization states is possible with diffractive optical elements ,9,15,16.iltering . In thisveplates ,19, whicveplates . Then, iq-plates for the generation of single cylindrically polarized laser beams, in this work, we used q-plates for the generation of a set of linearly polarized laser beams with different orientations of the polarization axis for each beam.In this study, we used thin films of azopolymers based on 9-carbazole (EPA) and dispersed orange DO3 azo dye  ,21. PrevThe high polarization sensitivity of this material allowed us to use it as a detector of the local polarization distribution. In addition, the use of non-uniformly polarized light for the processing of this material shows the possibility of the fabrication of ordered sets of microprotusions with predetermined orientations. This can be used for the formation of pre-designed relief patterns in thin azopolymer films for the high-throughput fabrication of diffractive optical elements and metasurfaces.f optical system for spatial filtering allows one to control the polarization state of each of the generated light spots independently  are the polar coordinates in the initial plane, k = 2π/λ is the wavenumber, λ is the wavelength, and  are the spatial frequencies that determine the positions of the diffraction orders in the Fourier plane. For the experiments, we designed a diffractive optical element splitting an initial linearly polarized Gaussian beam into a set of 24 light spots located on two circles (M = 2) with radii R1 and R2; the light spots were evenly distributed along the angular coordinate, with 8 light spots on the first circle and 16 light spots on the second circle.To design a diffractive optical element splitting an initial Gaussian beam into a set of light spots arranged in a circle, we used the method of carrier spatial frequencies  and a mof optical system with a polarizing filter, the light field polarization state in the Fourier plane undergoes some polarization transformations:Cin and Cout are the input and output polarization vectors, respectively, and Cin = T and polarization transformations corresponding to m-th order radial polarization [With light field modulation using a 4-ormation ,9,17,30.rization .ρ, ψ, z) are the cylindrical coordinates in the focal region,  are the spherical angular coordinates of the focusing system’s output pupil, Θ is the maximum value of the azimuthal angle related to the system’s numerical aperture, B is the transmission function, T(θ) = (cosθ)1/2 is the pupil’s apodization function of aplanatic systems, f is the focal length, and C(ν) = (xc(ν), yc(ν))T is the polarization vector after the implementation of the polarization transformation of Equation (2).Then, to calculate the components of the focused modulated light field, we used the well-known Debye approximation and Richards–Wolf formulas  are:(3)EThe profiles of surface relief formed on the surface of the thin azopolymers films are approximated well by a model proposed by Ambrosio et al., 2012 . HoweveroutP = 15 mW) was extended and collimated with a combination of two lenses, L1 and L2, with focal lengths of 25 and 150 mm. The collimated laser beam was directed onto the SLM with the help of mirrors M1 and M2. The 4-f optical system, consisting of two lenses, L3 and L4, as well as polarizing element PE, was used for the spatial filtering of the modulated laser beam. For the polarizing element, we used three different elements—a half-wave plate and first- and second-order q-plates. The half-wave plate allowed us to control the orientation of linear polarization of the field; the first- and second-order q-plates were used to generate polarization patterns corresponding to the cylindrical polarization of the first  and second orders. The polarizing element was located in the focal plane of lens L3. Thus, we had the ability to control the polarization distribution of each formed light spot and obtain different polarization patterns. The spatially filtered laser radiation was directed into the input pupil of a micro-objective, MO1 (NA = 0.40), with the help of mirrors M3, M4, and M5. The glass substrate S with a carbazole-containing azopolymer thin film was mounted on the 3-axis XYZ translation stage and located in the focal plane of micro-objective MO1. The thickness of the azopolymer thin films used was 1.5 µm. A system consisting of a light bulb, IB; a spherical lens, L6 ; a mirror, M6; and a micro-objective, MO2 (NA = 0.1), was used to illuminate the surface of the glass substrate. To observe the surface of the glass substrate with the carbazole-containing azopolymer thin film during laser writing, we used a system consisting of a beam splitter, BS; a lens, L5 ; and a video camera, CAM . A neutral density filter, F, was used to decrease the intensity of the observed laser beam.The optical schema of the experimental setup used for the laser patterning of the thin azopolymer films is shown in f optical system. These cases include the following polarization patterns: uniform linear polarization with angles of 0 and 45 degrees, first-order cylindrical polarization , and second-order cylindrical polarization. From the analysis of the patterns obtained for the linearly polarized beam, we can conclude that the orientation of each elongated microprotrusion formed was perpendicular to the direction of the local linear polarization at this point. More interesting results were obtained with the first/second order cylindrical polarization pattern—the orientation of the formed microprotrusions replicated the orientations of the polarization vectors of the first/second order cylindrical polarization rotated by 90 degrees. Observed distortion can be explained by the aberration of the optical system used in the experiment, the non-zero dimensions of each light beam in a set, manufacturing errors of the q-plates used, and incomplete correspondence of the wavelength of laser radiation (532 nm) to the central working wavelength of the q-plate used (515 nm). In fact, two parameters had major effects. The first one was the mentioned incomplete correspondence of the wavelength of laser radiation to the central working wavelength of the q-plate used. This led to an incomplete transformation of the initial linear polarization for each light beam in a set and small deviations between the orientations of the polarization vectors and the structures. The second one was the non-zero diffraction-limited dimensions of the generated light spots in a set at the Fourier plane of the used 4-f optical system. In this case, part of the used polarization filter illuminated by each light beam in a set performed a non-uniform transformation of the initial linear polarization. This led to the thickening of the formed microprotrusions. In addition, some nanoprotrusions on the film surface also affected the orientation of the formed structures. These nanoprotrusions can also affect the profiles and depth of the formed microprotrusions. Therefore, it is necessary to improve the thin film preparation procedure.Thus, azopolymer thin films show the possibility to detect not only the whole polarization state of the laser beam, which was shown previously, but also the local modifications of this state. It should be noted that, in this case, the formed relief profiles adequately approximated the longitudinal component of the illuminating beams shown in The results obtained show an interesting possibility for the realization of the parallel non-uniform patterning of azopolymer thin films with structured light. Previous demonstrations of the parallel fabrication of multiple nano- and microstructures in azopolymer thin films have been based on the use of interferometric lithography, which does not allow one to control the profile and orientation of each of the formed structures ,35,36. DThe next important step in the improvement of the proposed technique is the investigation of the effect of the decreasing distances between the formed light spots with different polarization states. The minimization of the effects of the interference between the closely packed light spots allows one to fabricate various diffractive optical elements and metasurfaces with high efficiency and minimal fabrication errors. In this case, as shown in this study and our previous studies, the control of the longitudinal component of the multiple generated light spots plays a vital role.An approach for the parallel fabrication of multiple microprotrusions with controlled orientation in azopolymer thin films was developed. The possibility of the control of the profile of each formed microprotrusion was shown experimentally and confirmed with atomic microscopy.Different polarization patterns, including linear polarization with two different polarization angles, the first- and second-order cylindrical polarization, were used to demonstrate and fabricate multiple microstructures located on two circles with different radii. Laser-written patterns on azopolymer films adequately reproduced the local changes in the polarization of the used structured laser beams in all cases.The calculated distributions of the longitudinal components of the structured laser beams used in the experiments were in good agreement with the profiles of the fabricated microstructures, which, once again, confirmed the possibility of using the longitudinal component of light to predict the shape of the microstructures formed in the thin azopolymer films. This also allows one to use azopolymer thin films as detectors of the polarization state of the illuminating laser beam—not only the entire beam as a whole but also its individual sections.Thus, the developed method provides the possibility to use pre-designed structured laser beams for high-throughput complex laser material processing. The method can be used for the fabrication of complex patterns of microprotrusions and the realization of complex-shaped diffractive gratings, diffractive optical elements, and metasurfaces.


All of these substances adsorb at the lipid membrane, while free-base and Zn(II) porphyrins actively generate singlet oxygen (SO) in the membranes. Thus, this study reveals a new way to tune the PDT activity of PSs in biological membranes through designing the structure of the peripheral groups in the macrocyclic photosensitizer.Photodynamic therapy (PDT) is a widely used technique for skin cancer treatment and antimicrobial therapy. An improvement in PDT efficiency requires not only an increase in quantum yield of photosensitizer (PS) molecules but also their applicability for biological systems. Recently, we demonstrated that the activity of porphyrin-based PSs in the lipid membrane environment depends on the nature of the cation in the macrocycle due to its interactions with the lipid phosphate moiety, as well as the orientation of the PS molecules inside the membrane. Here, we report the synthesis, membrane binding properties and photodynamic efficiency of novel dicationic free-base, Ni(II) and Zn(II) pyrazinoporphyrins with terminal tetraalkylammonium units ( Photosensitizers (PSs) represent a class of molecules capable of generating reactive oxygen species (ROSs), including singlet oxygen (SO), upon irradiation. This ability of photosensitizers allows them to be used in photodynamic therapy (PDT)—a method of killing pathogenic cells and microorganisms, widely used in the treatment of skin cancer ,2,3,4 anN-heterocyclic fragments to the periphery of the porphyrin macrocycle attracted synthetic efforts by our research group ethenyl-4′-pyridinium propanesulfonate, di-4-ANEPPS , were added into the opposing compartments of the cell from the stock solutions in ethanol. The total concentration of ethanol in the water never exceeded 3%. The porphyrins were added into the compartment far from the light source to prevent the attenuation of the light beam due to its absorption when passing through the water solution.The measuring cell was equipped with two windows: one for the optical monitoring of the formation of the BLM, and the other one for the illumination of the membrane with a semiconductor laser . The porphyrins and target molecule 6-[2- fluorescence spectrophotometer. Recently, we reported the comprehensive investigation of the synthetic strategy for the preparation of porphyrins fused with five- ,12,17 an2H-1 was selected for the investigation along with the corresponding zinc(II) Zn-1 and nickel(II) Ni-1 complexes. Ni(II) and Cu(II) ions are known to quench the photophysical properties of porphyrins completely through the fast irradiative relaxation of the excited states [Ni-2 provided the corresponding disubstituted pyrazinoporphyrin Ni-3, which in turn was successfully demetalated to give 2H-3 and further converted into the zinc(II) complex Zn-3. Interestingly, the ratio of the allyloxy to the γ-bromopropyloxy substituent increased upon condensation, and the contaminating allyl-substituted porphyrin was also inseparable from the target one. In this respect, the series of bis(bromopropyl) porphyrin derivatives was further subjected to quaternization through treatment using trimethylamine as a mixture. It is worth mentioning that the prolonged reflux in CHCl3 was required for the complete conversion of the starting bromoalkyl derivatives, and the yield of the target dicationic porphyrins remained low. It was found, for Ni-1 as an example, that a decrease in the reaction temperature through changing CHCl3 to CH2Cl2 prevented the substitution, while an increase in the temperature through performing the reaction in 1,2-dichloroethane resulted in a further decrease in the yield. Nevertheless, the target compounds 2H-1, Ni-1 and Zn-1 were successfully prepared with 37%, 42% and 28% yields of the quaternization stages. The final dicationic derivatives were successfully separated chromatographically from the monocationic by-products and, thus, obtained in a pure form.In this respect, a different strategy for the synthesis of the required dicationic pyrazinoporphyrin was proposed . Porphyrd states . However2H-1, Ni-1 and Zn-1 are collectively represented in Supporting materials  was used in further experiments with the BLM.We studied the influence of the ionic strength of the applied aqueous solutions on the aggregation of pyrazinoporphyrins with the analysis of changes in the UV–Vis spectra of porphyrins upon increase in the concentration of KCl in the 20–100 mM range . In all b measured with the IFC method. This indicated the adsorption of porphyrins at the BLM. The sign of the Δϕb corresponded to the adsorption of positively charged molecules that agreed with the structures of obtained porphyrins. The dependence of the Δϕb on the concentration of porphyrins added into the water solution is presented in b just after the single addition of the porphyrin solution with the given concentration. The comparison of three porphyrins showed maximal Δϕb values close to the In(III) complex of β-imidazolium-substituted porphyrin, which demonstrated the best membrane binding in our previous study [The addition of ethanol solutions of porphyrins into the cell compartment at one side of the membrane led to a change in the boundary potential difference Δϕus study . This reb. The illumination of the BLM with both adsorbed di-4-ANEPPS and porphyrin molecules led to a decrease in the Δϕb value due to the oxidation of di-4-ANEPPS molecules. This photooxidation was observed for the free-base porphyrin and its Zn(II) complex. As mentioned above, the Ni(II) complex was not capable of generating SO. The oxidation rate, R, was calculated from the kinetics of the decrease in the Δϕb during the illumination and its restoration after switching the light off [Lτ and Dτ are the time constants of exponents approximating the kinetics of ϕ(t) during illumination and the following dark phase, respectively. The dependence of R on the concentration of porphyrins in the water solution is presented in The photodynamic efficiency of the porphyrins was studied similarly to the early developed approach , throughight off ,28,29,30R increased with the concentration of porphyrins. The comparison of the values of R for Zn(II) and the free-base pyrazinoporphyrins demonstrated that the photodynamic efficiency of these two compounds were close. However, the oxidation rate did not reach the values of the In(III) complex of β-imidazolium-substituted porphyrin, which demonstrated the best membrane binding in our previous study [As follows from us study , and remIn the present work, we synthesized representatives of a new type of hydrophilic cationic porphyrins suitable for the PDT application in biological systems. Comparing pyrazinoporphyrins bearing terminal tetraalkylammonium units with β-imidazolium-substituted porphyrins, we demonstrated that cell membrane binding of PSs could be attenuated by their peripheral groups, in contrast to the previous findings, that it resulted only from the interactions of the central cation with lipid phosphate groups . However


Due to the clinically proven benefit of hyperthermia treatments if added to standard cancer therapies for various tumor sites and the recent development of non-invasive temperature measurements using magnetic resonance systems, the hyperthermia community is convinced that it is a time when even patients with brain tumors could benefit from regional microwave hyperthermia, even if they are the subject of a treatment to a vital organ. The purpose of this study was to numerically analyze the ability to achieve a therapeutically relevant constructive superposition of electromagnetic (EM) waves in the treatment of hyperthermia targets within the brain. We evaluated the effect of the target size and position, operating frequency, and the number of antenna elements forming the phased array applicator on the treatment quality. In total, 10 anatomically realistic 2D human head models were considered, in which 10 circular hyperthermia targets with diameters of 20, 25, and 30 mm were examined. Additionally, applicators with 8, 12, 16, and 24 antenna elements and operating frequencies of 434, 650, 915, and 1150 MHz, respectively, were analyzed. For all scenarios considered (4800 combinations), the EM field distributions of individual antenna elements were calculated and treatment planning was performed. Their quality was evaluated using parameters applied in clinical practice, i.e., target coverage (TC) and the target to hot-spot quotient (THQ). The 12-antenna phased array system operating at 434 MHz was the best candidate among all tested systems for HT treatments of glioblastoma tumors. The 12 antenna elements met all the requirements to cover the entire target area; an additional increase in the number of antenna elements did not have a significant effect on the treatment quality. Hyperthermia (HT) treatments, characterized as an artificially induced temperature rise of 40–44 °C typically for a duration of 60–90 min, have been proven to increase the survival rates of patients with a wide range of tumors when combined with radiotherapy (RT)  and/or cThe temperature increase in a tumor in microwave HT treatments is generally induced by the constructive interference of EM waves irradiating from applicators with a phased array consisting of antenna elements surrounding the treated area. Applicators operating from 434 to 915 MHz are the most common for HT head and neck  cancer treatments due to their ability to penetrate human tissues and generate a controlled heat focus within the tumor region ,8. RodriThere are several key design parameters in the optimization of HT phased array applicators; the most prominent are the operating frequency and the number of antenna elements. The relationship between these parameters is non-linear and their impact on the HT treatment performance is complex. Guérin et al.  demonstrThe purpose of this study was to evaluate the effect of the operating frequency and the number of antenna elements of a regional HT phased array system on the ability to create a clinically relevant distribution of the specific absorption rate (SAR) in and around the treatment target. For this purpose, we: (a) created a total of 4800 2D numerical models (scenarios) differing in anatomically and geometrically realistic patient-specific head models as well as the diameter and position of the tumor model, the number of antenna array elements, and the operating frequency ; (b) calInitially, 10 realistic 2D head geometries were created. These geometries were derived from 3D head models obtained from . The 3D We proposed two numerical models of the HT phased array applicator; the first model consisted of 24 antenna elements and the second model consisted of 16 antenna elements. The antenna elements were defined as a circular cross-section with a radius of 1 mm placed in an elliptically-shaped  phased array at an average of 3 cm from the surface of the head model. Henke et al. The maximization of the THQ, or the reduction of hot-spots;25, TC50, and TC75.The maximization of the target coverage, or an improvement in TCFor THQ optimization, we applied a PSO (particle swarm optimization) function available in MATLAB  with theThe SAR distributions for patient no. 1 with the hyperthermia target located in the frontal lobe 4 cm from the outer layer of the head model and a 12-antenna HT system are presented in 25 (50 (75 (1) and third (Q3) quartiles; the maximum and minimum values are represented with a vertical line facing upward and downward, respectively; and the median and mean values are represented with a horizontal line and a cross, respectively. The values were averaged for 300 samples comprising data from 10 patients, 10 target locations, and 3 sizes of target. A detailed statistical analysis of the TC parameters for the 12-antenna system is presented in 25 a, TC50 .The SAR focus quality was affected by the diameter of the hyperthermia targets. To obtain a target conformal SAR focus in smaller hyperthermia targets (below 25 mm) at 434 MHz was difficult due to the wavelength size in comparison with the target dimensions . The SARThe SAR TC depended on the depth of the tumor position rather than its specific area in the head . The 12-This study has several limitations. First, the use of 2D models: 3D models and simulations are more realistic. We used 2D models due to their lower computational requirements and thus time consumption. We explored thousands of scenarios that would be much more complex for 3D models. On the other hand, 3D models allow for the inclusion of other parameters that have no equivalent in 2D models; for example, the specific geometry of the antenna elements and the water bolus, the orientation of the antenna elements in space, and the corresponding polarization of the EM waves. These would introduce additional variables into this study and could ultimately reduce the generality of the results. Additionally, only numerical simulations without phantom measurements were used. However, from the experience of the authors, the agreement between the calculations and measurements was high in similar cases. The values of the evaluation parameters based on this study corresponded with the values that could be encountered in clinical practice. Lastly, deionized water was used as the matching medium and no other material was taken into account. On the other hand, none of the current HT systems use different materials. This is due to the low loss of EM waves passing through the deionized water, which is important for the low loss of microwave energy when EM waves pass through the matching medium.In this study, we investigated the ability of a single-ring HT applicator to deposit EM energy into a target located within the brain by assessing the effect of the HT system operating frequency, the number of antennae, and target position and sizes. We found that a 12-antenna 434 MHz system produced almost identical SAR TCs to the 24- and 16-antenna systems. Due to its lower complexity, we consider this to be the best configuration for HT phased array systems. We plan to expand the investigation with 3D simulations, multiple-ring antenna element configurations, and the testing of our numerical simulations in real-world measurements.


The epidemiological approach was adopted, supported by the positivism paradigm. Exposure variables were those directly related to breastfeeding and sociodemographic, family, maternal and child conditions. Data were collected by interview and analyzed by bivariate and multivariate statistics. The Hazard Ratio (HR) was calculated with a 95% confidence interval (95%CI). The tests were performed, admitting an error type I of 5%. The confidentiality of data was ensured.  the cumulative incidences of exclusive breastfeeding abandonment were 33.3%, 52.2% and 63.8%, at 2, 4 and 6 months, respectively. The variables that remain in the final multivariate model were maternal perception of milk quality , pacifier use , and time of first breastfeeding session .  the highest abandonment rate occurs before the fourth month. A perception of having poor-quality milk by the adolescent mother and pacifier use are factors that favor the abandonment of exclusive breastfeeding. Determining the factors associated with breastfeeding abandonment may allow their timely management, especially in more vulnerable populations. In the last three decades, Chile made sustained progress in its human development based on a balanced combination of economic growth and public policies; however, the country presents growing inequality and a 14.4 poverty rate--The rate of teen pregnancy in Chile has had a variable and worrying progression. According to official statistics, it increased consistently from 1990 to 2008 and then decreased slightly from that year until 2018The World Health Organization (WHO) recommends that mothers around the world exclusively breastfeed (EB) their babies for the first six months of life to achieve optimal growth, development, and health status. On a global scale, EB rates have been fluctuating, generating the global health target “Increase the rate of exclusive breastfeeding in the first six months of life to at least 50%”,In Chile, EB during the first 6 months of an infant’s life has been established as a health goal: to achieve EB for 60% of infants up to 6 months of age among the population attending community health centers (primary care). Currently, the prevalence of EB is far below the goals proposed by the Ministry of Health, possibly affecting the growth and optimal development of children belonging to more vulnerable populations, such as those of teenage mothersDetermining the factors associated with EB abandonment in adolescent mothers will allow for the timely management of these risk factors and favor better child growth and development, especially in more vulnerable populationsTherefore, the objective of this study was to analyze the factors associated with the abandonment of EB in adolescent mothers during the first 6 months of the infant’s life.The epidemiological approach was adopted, supported by the positivism paradigm.This is a prospective cohort study.Centros de Salud Familiar-CESFAM) in the San Bernardo Commune, located to the south of the Metropolitan Area of Santiago, Maipo Region of ChileThe study was conducted at the seven family health centers  and the southern Metropolitan Area (1%). Trends among 15-19 years teenagers (25.6%) are increasing, with figures higher than the country (22.2%) and the Southern Metropolitan Area (23.9%). Nowadays, the number of teenage pregnancies is decreasing in the rest of the country, but remains a significant public health problem in the study settingIn 2013, when this study was planned, San Bernardo had an estimated population of 319,517 people, of which 51% were female. The urban population percentage was 98.1%, with a birth rate of 16.3 The sample was calculated based on EB prevalence in 2013 between the first and sixth month of infants’ lives in the Commune of San Bernardo. The Health Corporation of the Municipality of San Bernardo reports that 76.4% of mothers breastfed their children in the first month of life, and by the sixth month of life, this prevalence drops to 48.6%For estimation, the criterion of marginal homogeneity was used according to the McNemar test, which compares paired proportions with α = 5% and a power of 80%. The resulting minimum number of mothers and infants who should be included in the study was 105.The sample was stratified according to the number of evaluations of healthy children at each health center. For this stratification, the estimated proportion of adolescent mothers in the district of San Bernardo (17.2%)Adolescent mothers who met the following criteria were included in the cohort: age between 15 and 19.5 years at the time of delivery, non-twin child, medical discharge from the maternity ward along with the infant, no difficulties with the infant’s maternal latch due to illness or a fetal malformation, EB at time of discharge from the maternity ward, capable of understanding what was asked and free of communication difficulties.The participants were enrolled by convenience when taking the two-month infant for consultation. The researcher was on different days in each health center, and the adolescent mothers who arrived were asked about the inclusion criteria. When the sample size was complete, the enrolment process was stopped.Firstly, the adolescent mothers were invited to participate and signed an informed consent form.The participants who attended the 2-month child well-being evaluation (between 55 and 65 days of life) and met the inclusion criteria were included in the cohort. Mothers who continued with EB at 4 months (between 115 and 125 days) and 6 months (between 175 and 185 days) of the infant’s life were followed.Data were collected from October 2014 to March 2016 via an interview conducted by one of the researchers using a questionnaire. This questionnaire was previously tested (with 10 mothers not included in the cohort) to confirm the adolescent’s understanding of the questions. It considered all the variables investigated and was used for each study stage . The questionnaire had two parts: one about general antecedents that were requested once because they did not vary in time , and the other that was adopted during the follow-up. This instrument was developed using based on a literature review, considering the variables affecting breastfeeding abandonment.The exposure variables were: return to school (continuity of studies after delivery); living with the mother or mother-in-law (at the moment of the interview); stable partner (away from the partner during pregnancy and after delivery); pain when breastfeeding (any time); cracks in the nipple (any time); maternal perception of milk quality  and maternal perception of the child’s satisfaction when breastfeeding (considering her opinion); receiving education on breastfeeding during the pregnancy and postpartum ; cesarean section; skin-to-skin contact (immediately after childbirth); pacifier use (any time); postpartum consumption of illicit drugs ; time of first breastfeeding session ; hospitalization of the newborn (after discharge).The abandonment of EB and the infant’s age at the time of EB abandonment were considered outcomes. EB was considered if the infant only receives breast milk without any additional food or drink, not even water.The consistency analysis of data was made to each variable by identifying codes not allowed for the field. Inconsistencies were corrected using the information contained in the instrument.Descriptive analyses of the variables were performed using frequency and percentage analyses. The accumulated incidences of EB abandonment for each month of follow-up  were calculated.Values between the variables were compared using the log-rank test. This comparison was made to evaluate the survival differences according to the categorical variables that were theoretically interesting to explore regarding the EB status over time. Survival curves were obtained using the Kaplan-Meier estimator.All the variables that presented p-values ≤ 0.10 were considered for constructing the multivariate model. The Cox proportional hazards survival modelThe tests were conducted using a type 1 error probability and p ≤ 0.05 was adopted.The Research Ethics Committee of the School of Nursing at the University of São Paulo, Brazil, and the Scientific Ethics Committee of the South Area of Santiago, Chile, approved this study. Mothers’ participation was voluntary and followed all the determinations, ensuring the protection of the rights of all involved in the research.The measures taken to protect data confidentiality included privacy at the location of the interviews, the anonymity of information by coding the participants in the database and the restriction of data access to the researchers.In this study, 248 adolescent mothers were evaluated for eligibility in seven CESFAM locations in the Commune of San Bernardo; 125 did not meet the inclusion criteria, and 18 refused to participate. Thus, 105 participants and their 2-month-old children were included in the cohort and followed at 4 months (n=70) and 6 months (n=47) between October 2014 and March 2016.Regarding the ages of the participants, 51.4% (n=54) were less than 17 years old, 95.2% (n=100) had completed primary education, and 65.7% (n=69) had normal childbirth.Of 105 (100%) participants, 35 (33.3%) had already abandoned EB when the infants were 2 months old. At 4 months of the 70 (100%) participants who remained in the study, 23 (32.9%) had incorporated another food, and at 6 months, of the 47 (100%) mothers who remained, 9 (19.1%) had added another food. The remaining 38 (80.1%) participants were continuing EB. Thus, the EB dropout rates were 33.3%, 32.9%, and 19.1%, at, respectively, 2, 4 and 6 months.The number of mothers who abandoned EB every month, up to the 6-month evaluation point is presented in The bivariate analysis of the exposure variables and the information regarding abandonment at 2, 4 and 6 months is presented in Variables with statistically significant values included return to school (p=0.004), cracks in the nipple (p=0.045), maternal perception of milk quality (p<0.001), maternal perception of the child’s satisfaction when breastfeeding (p<0.001), pacifier use (p<0.001), postpartum consumption of illicit drugs (p<0.001), and time of first breastfeeding session (p=0.032). Variables with p < 0.10 were tested in the multivariate analysis. Given its p-value in the bivariate analysis, cesarean section and child hospitalization were included .As shown in Next, the EB survival analysis graphs were created for the final model’s significant variables -3. The lParticipants who perceived that their milk was of good quality showed higher EB survival than those who perceived that the quality of their milk as regular or bad . Particivs 43.1%)The present study showed an abandonment rate of EB among participants at 6 months that was greater than the national mean reported by the Ministry of Health . This outcome is inconsistent with a study conducted in Spain, in which 53.7% of the cases studied maintained EB until 4 months of ageConcerning demographic variables, the participants’ ages were mainly between 15 and 16 years old. This outcome is consistent with the maternal demographics of the country, where an increase in adolescent pregnancies at younger ages is foundThe consumption of alcohol, tobacco and illicit drugs (marijuana and cocaine) during pregnancy was lower than the typical rates found among adolescents in ChileRegarding the variables directly associated with EB abandonment in this study, a few participants returned to school at 2 and 4 months (11.4%), whereas a third of those who continued EB returned to school at 6 months. In Chile, school dropouts tend to occur before and during pregnancy, with low reintegration schoolConcerning the mammary difficulties evaluated, cracks in the nipple significantly influenced EB rates, being consistent with the findings of a systematicThe maternal perception of breast milk quality and the satisfaction of the infant with EB are two closely related variables that directly involve maternal perceptions, which is consistent with the findings in a longitudinal descriptive study in a Spanish settingPacifiers as a risk factor for EB abandonment has been amply demonstratedThe time of first contact, namely, mothers who had contact in the first 15 minutes after birth versus those who had contact after the first 15 minutes, showed a significant relationship with EB. In a recent systematic review and meta-analysis, the quantitative analysis showed that skin-to-skin contact between mother and child had a significantly positive effect on the success of the first lactation and duration of the first lactation-Other studies in Indonesia determined that an early start to breastfeeding has a statistically significant relationship with EB, where early-onset was considered less than 1 hour after birthThe initiation of physical contact within 15 minutes is related to having a natural childbirth and immediate skin-to-skin contact. The response regarding timing in this question is based on the mother’s memory and perception and was considered to have occurred immediately when it took place within 15 minutes.A cesarean delivery resulted in a tendentially significant relationship with the abandonment of EB, consistent with what was found in Spain, where cesarean sections were associated with a lower likelihood of EBRegarding this study’s limitations, the possibility of bias and the restricted generalization power should be considered.Regarding the selection bias, it refers mainly to the mode of including the participants, which was for convenience. About implementation, limitations in data collection  were minimized by using a private room for the interview and because a single researcher, who is not part of the health team, collected all data. Nevertheless, the information bias may be present when the participant provided a socially expected response or wanted to please the researcher . Concerning the interpretation of the results, the confounding bias was minimized by using multivariate analysis. In turn, even if the sample had been estimated with adequate parameters, the reduced number of participants at 6 months of infant life-limited an optimal statistical power.As for the generalization of the results, although teenage pregnancy rates are similar in the different urban regions of Chile, San Bernardo’s reality and life conditions are worse  than in other sectors of the metropolitan region, where living conditions are better, with more excellent resources. Despite these, we consider it possible to generalize the main results.Although the findings of this cohort are relevant, an interval shorter than 2 months to follow the abandonment of EB and the participation of adolescent mothers with diverse social characteristics could provide accurate data on the duration of EB in the first 6 months.This study advances the understanding, by nurses and other health professionals, of the abandonment of breastfeeding in the most vulnerable populations. By achieving more excellent knowledge about the causes that affect abandonment, we will be able to generate strategies that allow a greater prevalence of exclusive breastfeeding.As determined in this study, the EB abandonment rate for adolescent mothers at 6 months is higher than the national EB abandonment rate in Chile. The highest abandonment rate occurs before the fourth month. Therefore, EB promotion strategies must be adopted from the beginning of the pregnancy and, specifically, during the first three months of the infant’s life.Of the group of variables related to the abandonment of EB that were considered, only two were confirmed among the participants in this cohort.The perception of milk quality and pacifier use are two variables that can be addressed through education during pregnancy. The type of education delivered is essential, but the transmission of knowledge and not just providing information should be the aim.The moment of first physical contact between the mother and child is vital because it is associated with a more natural birth centered on the woman and her child but is not on the routine procedures that become a priority in many cases.


The methods of cyclic voltammetry, electron microscopy, including determination of the elemental composition of the studied objects, and X-ray diffraction analysis were applied for the present study. The reduction degree of rare-earth metal (REM) oxides was determined using both the bromine method and reduction melting of the samples in the graphite crucible. The formation of the metallic phase composed of the rare-earth elements (REEs) was not observed even at the cathode potentials, corresponding to the formation of the liquid alkali metal phase, and lithium extraction, which, in the quantitative ratio, exceeds greatly the values needed for the reduction reaction. CeO2 was found to reduce to Ce2O3.The reduction of pellets composed of individual CeO The operation of fast neutron reactors is inextricably related with the development of the closed nuclear fuel cycle based on the processing of highly active spent nuclear fuel (SNF) and returning uranium and plutonium fuel back to operation . PyrocheUranium oxide was found to be completely reduced to metallic uranium ,7,8,9. H2 and Nd2O3, as well as the La2O3-Nd2O3-CeO2 mixture without the presence of any other metal oxides.This paper is devoted to the analysis of the reduction processes of individual CeO2O melt:The following reaction takes place at the cathode during the electrolysis of the LiCl-Li2O3, according to reaction (3), lithium oxide dissolves in the chloride melt. A decrease in the lithium oxide concentration shifts the equilibrium of the system toward the formation of rare-earth metals. That is why pure lithium chloride was chosen as the initial melt for the first test run. A glassy carbon rod was used as an anode, where the following reaction takes place:Extracted lithium interacts with REM oxide; for instance, with NdFrom then on, a dense ceramic anode based on nickel oxide doped by lithium oxide was used in the oxide-chloride melt ,16, and Chemically pure anhydrous lithium chloride containing 99.3 wt.% of the basic component was used. To remove water traces, the salt was hermetically sealed, heated stepwise, and melted in an argon atmosphere. To remove the remaining oxygen admixtures, we used the method of zone melting in a nickel boat under the flow of argon purified from oxygen traces and water vapors . ChemicaThe REM oxide pellets had a porosity of 40–50% and the following dimensions: height of 2–4 mm and diameter of 10.1–10.2 mm. The pellets were pressed from the REM oxide powder of the 5 ÷ 20 µm fraction under the pressure of 370–650 MPa. Zinc stearate was used as a binding agent. Then, the pressed pellets were annealed in air at a stepwise heating rate of 150–200 °C per hour up to 1200 °C and were exposed for 2 h at this temperature.15) was put on the bottom of the cylinder. A mixture of LiCl-Li2O (0.0–0.1 wt.%) amounting to 200–300 g was loaded into the container. Depending on the purpose of the experiment, either a ceramic or metal container was used. For example, in experiments on the Nd2O3 pellets reduction in the melt without initial lithium oxide content (0 mol.%), a ceramic MgO container and the glassy carbon anode were used. Chlorine gas was released on the glassy carbon anode.13) was made of high-purity dense MgO ceramics and the outer tube (17) was made of quartz glass. The outer tube was installed into a fluoroplastic cover (2) of the electrolytic cell. A glassy carbon rod of 6 mm in diameter or a rod of 10 mm in diameter composed of gas-resistant NiO-Li2O ceramics served as an anode (14). The anode was located inside the MgO ceramic tube. The anode part was partially immersed into the electrolyte (16). A platinum wire of 1.00 mm in diameter served as a current lead (11) to the NiO-Li2O ceramic anode. The wire was fixed in a special cavity in the upper part of the anode. Different types of anodes were chosen for different experiments depending on the problem to solve.The anode assembly was made of two tubes inserted into each other: the inside tube (9). The cathode was placed on the bottom of a MgO ceramic crucible (7). A molybdenum wire current lead (6) to the cathode was used. Small openings in the side walls of the crucible facilitated the electrolyte diffusion through its walls. To perform the electrochemical measurements, mainly, to measure the cathode and anode potentials during the electrolysis or other manipulations, we used a Bi-Li (60 mol.%) reference electrode (5). Bismuth was placed in a MgO ceramic tube (18) with a small opening in the bottom part. We used a Mo wire current lead to the reference electrode. The alloy was prepared directly in the electrolytic cell before the electrochemical reduction of REM oxides. When the electrolytic cell was assembled and the electrolyte was melted, the reference electrode was immersed into the melt to provide contact with the electrolyte through an opening in the MgO tube (18) illustrated in 18). When the reference electrode was formed, it was lifted so that the openings in the ceramic tube were above the melt surface [A circle metallic nickel plate or intercoiled Mo wire served as a cathode  and «PGSTAT AutoLab» . The anode potential was controlled by a universal digital voltmeter GDM-78351 . The electrolyte was sampled during the experiment; the concentration of lithium oxide was determined in situ by the acid–base titration method. The chemical analysis of the solutions was performed by an emission spectrometer with the inductively coupled plasma, «Optima 4300 DV» . The bromine method was used to determine the reduction degree of oxides . Apart f2O3 (described by reaction (3)), CeO2 oxides, and their La2O3-Nd2O3-CeO2 mixture, as well as the voltammograms of the auxiliary Mo electrode. The obtained results are illustrated in First, we determined the potential of the reference electrode relative to the potential of lithium extraction on the Mo electrode. Then, we recorded the voltammograms of the cathode samples composed of individual NdParameters and regimes of the experiments on the electrochemical reduction of REM oxides are presented in 2O in the melt ranging from 0.0 to 0.8 wt.% and at different amounts of the electric current (Q) passed ranging from 136 to 201% of the theoretical value  and (3)).2O3 pellets were reduced in the pure LiCl melt. Lithium oxide was not added to the initial melt. In this process, the MgO cathode container and glassy carbon anode were used. During the reduction process, gaseous chlorine evolved on the glassy carbon anode. The changes in the cathode potential are illustrated in The Nd2O3 pellets before the electrolysis. The fragments of the pellets on the Ni cathode after the electrolysis are presented in 2O3 pellet. 2O3 pellet recorded before the electrolysis. This fact testifies that the analyzed Nd2O3 pellet fragment did not undergo any changes.2O3 pellet and, hence, complex alloys containing mainly lithium, magnesium, and nickel formed.We performed a chemical analysis of the metallic films that covered the pellets surfaces and the current lead as well as the surface of the ceramic insulator of the current lead to the Ni cathode and the surface of the MgO ceramic crucible under the Ni cathode. The films were dissolved in water. The combination of the elemental chemical analysis and X-ray diffraction data brought us to the conclusion that under the experimental conditions, the MgO ceramics was reduced instead of the Nd2 pellets before and after the reduction. The samples after the reduction had mainly a yellow-orange or brown color, which are typical for Ce2O3 [or Ce2O3 ,20. This2O3-CeO2-Nd2O3 mixture in the 1:1:1 ratio. 2O3 oxide formation.2 and with Nd2O3, the current lead was covered with metallic film composed of lithium and magnesium alloy.In the aforesaid experiments, the bottom part of the Mo current lead was intercoiled, as presented in After the vacuum distillation of lithium chloride from the pellet surface, fragments of the samples from different experiments were analyzed using a TESCAN MIRA 3 LMU microscope . The results of the analysis are provided in 2O3-CeO2-Nd2O3 pellet after the electrolysis and subsequent distillation in the resolution of 100 µm, and The analysis of the results obtained using the TESCAN MIRA microscope  and those reported in 2 reduction are of great importance as they allow us to identify them with the PuO2 reduction. According to the thermodynamic analysis, CeO2 reduction is possible [2.The obtained results on CeOpossible  and, the2 reduction. It is important to understand that the end product of the PuO2 reduction may be composed of metallic Pu and plutonium sesquioxide, in the case when the reduction process is incomplete. This is vital for determination of the PuO2 reduction by the bromine method.However, it was experimentally shown that cerium reduced only up to the cerium sesquioxide, and further reduction to metal did not take place. Therefore, the oxides reduction proceeded subsequently via oxides with the smallest oxygen concentration, and the strongest oxide would become the limiting link of the chain. Thus, we may predict to a certain extent the possibility of PuO2 reduction to its sesquioxide is highly probable, for instance, it is more thermodynamically likely than that of UO2 reduction to metal (reactions (1) and (9)). In the case of uranium, the anode peak of the extracted lithium dissolution was clearly absent on the voltammetry curves, which is explained by its consumption during UO2 reduction. The analogous picture was not observed for cerium. We suppose that this fact may be associated with the formation of a separate individual metallic uranium phase, where lithium was extracted; this process, obviously, also took place in the volume of the porous sample. Even at the reduction of highly dense UO2 samples, a porous layer of the metallic uranium phase, which did not prevent the following reduction, was formed at their surfaces. The processes related with cerium are more complex: cerium dioxide transforms into intermediate oxides  [It was found that the CeOCeO1.66) , which f(Ln−Ln) is the weight of the lanthanide in the metallic phase and m(Ln-Ln2O3) is the weight of lanthanide in the oxide phase.It is crucial to determine the reduction degree (β) of the REM oxide samples, i.e., to determine the relation of the formed metallic phase to the total amount of REM metal in the sample.A bromine method is recognized in many papers as promising for analyzing the metallic uranium-uranium dioxide system ,13,14. AIt is seen that the studied samples may contain up to several wt.% of REM metallic phase. However, the X-ray diffraction patterns illustrated only cerium and neodymium oxide phases. In addition, this was characteristic both for the pellets containing the electrolyte and those rinsed in dehydrated alcohol or distilled in vacuum. In all cases, the X-ray diffraction patterns were recorded in hermetically sealed sample holders  with an inert atmosphere. The fragments of the pellets after the vacuum distillation of the captured electrolyte were studied using the electron microscope and their elemental composition was determined. It was found that cerium and neodymium appeared to be bound only with oxygen. The concentration ratio was close to the theoretical one for the corresponding oxides. Therefore, the data obtained using the bromine method contradicted with the data obtained using the other mentioned methods. That is why, using the bromine method, we determined the amount of metallic and oxide phases in the model objects, composed of the known amount of each phase , and in 2, Ce2O3, and Nd2O3 bromating reactions [The obtained results illustrate that the bromine method used to determine the degree of REM oxides reduction provided unstable and significantly inflated results. The dispersion degree influences the value of the reduction degree of oxides to metals when the bromine method is applied. That is why this method can be hardly used to analyze REM oxides, because of the difficulties associated with the results interpretation. The flawed data are mainly obtained at the analysis of oxide powders rather than highly dense pellets. However, after the lithium electrolytic reduction in the melt, simulated mixed oxide fuel and SNF pellets transform into the oxide powders. The thermodynamic analysis of the UOeactions  elucidatIn addition, we shall consider the fact that during the real experiment, the solutions of bromides in ethyl acetate are formed rather than their solid phases, as presented in equations. This promotes the shift in the equilibrium of reactions (11)–(14) to the right side.(gas) and CO2(gas). The gaseous products are carried to the catalytic converter by the helium flow. Helium and carbon dioxide are the output gases from the catalytic converter. The concentration of carbon dioxide was quantitatively determined by the infrared spectrometer of LECO OH836  and METAVAK-AK . First, the oxygen concentration in the individual CeO2 and Nd2O3 oxides samples was measured. The measurement results were in good agreement with the theoretical values. Then, we measured the oxygen concentration in mixed REM oxide samples. All samples preparation procedures were performed in a glove box in an inert argon atmosphere containing less than 10 ppm of oxygen and 0.1 ppm of water vapor. The measurement results are presented in Therefore, it becomes obvious that new methods for the reduced products analysis are required. That is why we determined the remaining oxygen content in the reduced sample, rather than the concentration of the obtained metal. We used the method of high-temperature melting of the sample in a graphite crucible. This method is well known. The sample is loaded into a graphite crucible and melted at high temperatures reaching 3000 °C in the flow of helium. During this process, the sample interacts with carbon, which results in the formation of gaseous carbon oxides CO2 transforms into Ce2O3. The experimentally determined oxygen concentration in the reduced sample was in good agreement with the theoretical value, calculated following the aforesaid assumption.To calculate the concentration of oxygen in the samples, we assumed that after the reduction, CeO2O3, CeO2, and Nd2O3 are not reduced to metals during the electrolysis.Therefore, the provided calculation results and the experimentally obtained values of the oxygen concentration testify that La2O concentration in the melt did not exceed 0.7 wt.%, it may be easily calculated that oxygen added to the sample via alkali metal oxide, i.e., Li2O present in the electrolyte, changed the total oxygen concentration by less than 0.1%. This correction was furthermore less for the samples subjected to the vacuum distillation.We should note that the pellets were impregnated with the electrolyte after the reduction. The weight of the mixed REM oxide pellets increased by 11%. Considering that the Li2 and Nd2O3 as well as the mixture of La2O3-CeO2-Nd2O3 in lithium chloride melt with minimal LiO2 concentration was studied. It was experimentally found that the REM oxide pellets did not reduce to metals even at the Li2O concentration of zero. Lithium- and magnesium-containing alloys were formed as a result of the MgO ceramics metallization. Cerium dioxide was found to transform into its sesquioxide. The determination of the degree of metallization of the initial reagents during the reduction process is a key research parameter. However, this aspect requires further research and development. That is why, together with the known detection methods for determination of the metallic and oxide phases’ ratio in the uranium system, the method aimed at the determination of the remaining oxygen concentration in the end product was considered. The provided conclusions were verified by X-ray diffraction analysis, micro-X-ray analysis with scanning electron spectroscopy, elemental analysis, and high-temperature reduction melting of the sample in the graphite crucible.The electrochemical reduction of CeO


Clarifying the influence of the dress process parameters of the abrasive water jet on the dressing effect of fixed-abrasive pads (FAPs) is a prerequisite for online controllable dressing of abrasive water jets. This paper uses three factors and three horizontal response surface methods to explore the influence of jet pressure, abrasive concentration, and nozzle angle on FAP dressing quality. The prediction model of the material removal rate of a FAP machined using three process parameters is established. The influence of pairwise interactions of the three process parameter variables on the dressing effect and the optimal process parameters under each target is analyzed. Finally, the optimal process parameters predicted by the model are verified by experiments. The results show that the best dressing parameters with the MRR of the workpiece as the response value are as follows: jet pressure 3.8 MPa, abrasive concentration 3%, and nozzle angle 73°. The predicted value of the optimal process performance is 464.574 nm/min, and the experimental verification result is 469.136 nm/min; the error between the experimental value and the predicted value is within a reasonable range. Fixed-abrasive machining technology has the advantages of minor subsurface damage, small surface shape error, and controllable wear particle trajectory, so it is widely used in ultra-precision machining ,2,3,4. HPresently, the conventional dressing technology of FAPs can be divided into two categories : self-drTo summarize, although existing dressing technology has made some progress, there are still some deficiencies. There are some defects when dressing with diamond dressers, such as the low service life of the lapping and polishing pad, easy scraping of the workpiece , low dreThe W7 diamond FAP with 30% copper content was used in the dressing test; its main composition and mass fraction percentage are shown in The abrasive water jet dressing system used in the dressing test was designed and built by us, and was mainly composed of a power system, an abrasive supply system, a sprinkler system, and a motion control system. Its principle and physical designs are shown in X1, abrasive concentration X2, and sprinkler angle X3. The selected levels of these three factors were: X1 3 MPa, 4 MPa, and 5 MPa; X2 3%, 5%, and 7%; and X3 60°, 70°, and 80°. The material removal rate of quartz glass, processed for the first time by the FAP with different process parameters, was taken as the response value. The 1 level, 0 level, and −1 levels of each processing parameter variable were represented by Xip2i, Xtun0i, and Xtun1i, respectively. The above three parameters were coded using Equation (1):The self-built jet system was used to carry out the dressing test, and the method used in this test was the response surface method Box–Behnken design (BBD), the principle of which can be found in reference . The facThe dressing effect of the FAP is directly related to the processability of the quartz glass after finishing. That is, the better the dressing effect of the FAP, the better the processability of the quartz glass. Therefore, the material removal rate of the quartz glass processed by the FAP was selected as the quantitative evaluation index of the dressing effect of the FAP. The surface morphology of the FAP before and after dressing and the surface morphology of processed quartz glass were selected as the qualitative evaluation index of the dressing effect of the FAP.The quality of the quartz glass samples before and after processing was weighed using the SatoriousBSA2245-CW precision electronic balance (0.1 mg), and the material removal rate MRR was calculated via the “weight loss method” (Formula (2)):A Leica DVM6 ultra-depth-of-field microscope was used to detect the surface morphology of the FAPs before and after finishing, without factor level, and a ContourGT-X3/X8 white light interferometer was used to detect the surface morphology of the quartz glass before and after finishing, without factor level.X1, abrasive concentration X2, nozzle angle X3, and material removal rate of quartz glass were converted into matrix form, and the regression coefficient was obtained using the least square method. The multiple regression equations of jet pressure X1, abrasive concentration X2, nozzle angle X3, and the material removal rate of quartz glass was obtained, as shown in Equation(3).Before dressing, the material removal rate of the FAP-machined workpiece was significantly reduced after being blunted by the marathon experiment, and the material removal rate of its lapping quartz glass was about 150 nm/min. The material removal rate of quartz glass machined by the FAP after dressing with different process parameters improved, and the material removal rate of quartz glass processed for the first time by the FAP after dressing with different process parameters was used as the evaluation index; the test results are shown in p-value is the significance level of the factor. It can be seen from 2 = 0.9570, and the adjustment determination coefficient X2 and X12 in Equation (2) were highly significant at the significance level of p < 0.01; X1, X32, and X1 ∗ X2 were significant at the p < 0.05 level, indicating that the relevant factors and their interactions had a significant influence on the material removal rate of quartz glass.This section presents the significance test and variance analysis using Formula (3). Using the significance of the variance and correlation coefficient judgment in Formula (3), the results of the material removal rate regression model variance analysis of the obtained quartz glass are shown in According to the experimental results in The optimum process parameter ranges of jet pressure, abrasive concentration, and nozzle angle analyzed in The response surface and contour map can accurately analyze the jet system’s best range of process parameters, and when combined with the regression model, can optimize the process parameters of the jet system.After optimization, the best process parameters corresponding to quartz glass’s maximum material removal rate are jet pressure 3.8 MPa, abrasive concentration 3%, and nozzle angle 73°. That is, these process parameters are the best FAP dressing process parameters.By substituting the predicted optimal process parameters into the regression model, the predicted material removal rate of quartz glass is 464.574 nm/min. The experimental results show that the actual material removal rate of quartz glass is 469.136 nm/min. The predicted results are very close to the actual experimental results, except for a difference of 4.562 nm/min.The response surface model established in this paper has high accuracy and can be used to predict the results of an abrasive water jet dressing FAP.Through analysis of the response surface and contour map, the range of the best process parameters could be analyzed accurately, and the regression model could be used to optimize the process parameters. The following conclusions were drawn: