Pseudomonas aeruginosa in excisional cutaneous wound in mice.To evaluate a biofilm model of Preclinical, translational study conducted with 64 C57BL/6 mice randomly assigned to control and intervention groups. Evaluation was on days D0, D3, D5, D7 and D10 of wound making. The profile of biofilm formation and induction was evaluated using wound closure kinetics, quantitative culture, and evaluation of wounds using transmission electron microscopy (TEM). Clinical evaluation was performed by liver tissue culture, weight variation, and quantification of leukocytes in peripheral blood. Analyses were performed with GraphPad Prism software.P. aeruginosa and survival of animals was 104 UFC·mL-1. In D5 (p < 0.0001) and D7 (p < 0.01), animals in the intervention group showed a delay in the healing process and had their wounds covered by necrotic tissue until D10. Statistical differences were observed in wound cultures and weight at D5 and D7 (p < 0.01). Liver cultures and leukocyte quantification showed no statistical differences. No bacteria in planktonic or biofilm form were identified by TEM.Bacterial load for induction of infection with The findings raise questions about the understanding of the ease of formation and high occurrence of biofilm in chronic wounds. Inspection is a controversial pointin vitro and in vivo studies are important tools for evaluating and producing knowledge about biofilm. The use of in-vitro systems has allowed significant advances in understanding how antibiofilm agents work and serve as a premise for conducting more robust in-vivo clinical studies, such as preclinical trials and controlled clinical trials.Experimental in-vivo  studies have been recommended as an alternative for questions from bench research to clinical research, providing a powerful basis to aid clinical decision makingThe results of studies published to date have not been sufficient to elucidate gaps in biofilm management and management in clinical practice. From this perspective, in-vivo biofilm became a cost-effective proposition when compared to the cost dimension of a clinical trial. Some researchers,The choice for the skin wound model with The creation of a feasible wound biofilm model is essential for a better understanding of the mechanisms involved in the processes of inflammation, angiogenesis, and tissue repair. It is believed that the biofilm model will subsidize the development of alternative studies to evaluate the effects of antimicrobial agents on biofilms, comparative studies to evaluate interventions that result in the reduction and elimination of biofilms. The results of these studies may yield improvements for the clinical management and management of biofilm in chronic wounds in clinical practice.Pseudomonas aeruginosa in excisional cutaneous wound in mice.In order to advance this area of knowledge, this research aimed to evaluate a biofilm model of The research was approved by the Ethics Committee on Animal Use of Universidade Federal de Minas Gerais (UFMG), under protocol number 87/2015. Upon completion of the wound biopsies and tissue collection for the proposed evaluations, the animals were euthanized according to the recommendations of the Ethics Committee on Animal Use of the UFMG and National Council for the Control of Animal Experimentation Normative Resolution No. 37, 2018.This is a preclinical study, translational in nature. The experimental procedures were carried out in the Angiogenesis and Stem Cell Laboratory of the Department of Physiology and Biophysics and in the Laboratory of Biotherapeutic Agents of the Department of Microbiology, both at UFMG. The biofilm evaluation was performed at the Microscopy Center of UFMG.P. aeruginosa American Type Culture Collection (ATCC) 25853 (ATCC 25853), sample  provided by the Laboratory of Biotherapeutic Agents, Department of Microbiology, UFMG.The bacterium used was P. aeruginosa was propagated in 5 mL of brain and heart infusion (BHI) broth medium (manufacturer Acumedia) and grown in a microbiological oven for 24 h (overnight) at the temperature of 37°C,The sample of Pseudomonas broth with 3.4 × 109 CFU·mL-1 and 200 μL of sterile 80% glycerol. These aliquots were immediately stored in a -20°C-freezer and used in all further experiments in this study.Serial dilution of this bacterial solution was performed to count the colony forming units (CFUs) per gram of tissue. Aliquots were prepared in cryotubes (2-mL capacity) containing 800 μL of the 4 CFU·mL-1 was applied. The control group received the same filter with 10 μL of phosphate buffered saline (sterile vehicle) to mimic and simulate wound infection.Biofilm induction on the wounds was performed by applying a sterile cellulose filter (membrane) with a thickness and porosity of 0.2 μm, measuring 5 mm in diameter, in which 10 μL of the bacterial suspension containing 10The animals were provided by the Vivarium Center (CEBIO) of UFMG. To carry out the experimental procedures, the animal welfare parameters were considered according to the recommendations of Technical Guidance No. 12, from the year 2018, of the National Council for the Control of Animal Experimentation of Brazil.n sample of eight animals for each experimental group. A 20% error and replacement percentage of sample loss over the n were considered.The mice were healthy, isogenic, male, C57BL/6 mice, aged approximately 8 to 12 weeks and with a body weight between 20 and 30 g. The sample size was calculated from the analysis of a 95% confidence interval for the mean (significance level of 5%) and an 80% chance of detecting a difference between the means, that is, a statistical power of the test of 80%, considering a n sample size of 64 animals.The animals were randomly divided into two study groups, called control group (Pbs) and intervention or infected group (Pa). The proposed procedures were applied to both groups, and time follow-up occurred at five different times: 0, three, five, seven and 10 days, totaling a The animals were anesthetized and then submitted to hair trichotomy with a minitrichotomizer  and asepsis of the skin on the dorsal region with 70% alcohol solution. Subsequently, four wounds were made on the mid-back region of these mice with the aid of a sterile surgical punch with a diameter of 5 mmThe experimental procedures were carried out from January 2019 to July 2020.4 UFC·mL-1. In both groups, the respective solutions were applied to the cellulose filters placed over the four wounds, as adapted from the biofilm infected wound modelIn the animals of the control group, 10-μL phosphate buffered saline (vehicle) was applied, while the animals of the infected group received 10 μL of the bacterial suspension containing 10At the end of the first 24 h, the filters were removed from the wounds, and the wounds were again occluded with the transparent film. This cover was changed on days 3, 5, and 7 of each experimental time period to measure and evaluate the wounds, and then the transparent film was reapplied. The end of the experimental follow-up occurred on the tenth day.Day 0  was when the wounds were made, and the other times were considered as Day 3 (3-day follow-up), Day 5 (5-day follow-up), Day 7 (7-day follow-up), and Day 10 (10-day follow-up) after the wounds were made. These experimental times are important markers for monitoring biofilm induction and formation in the wound healing process.The wound closure profile was performed by photographing and measuring the area of the wounds on days 0, 3, 5, 7 and 10. A digital caliper (Insize) was used to measure the wound area. The results were expressed as percentage of closure relative to the original wound size, using the P. aeruginosa in the wound bed was performed by means of the macerate culture technique of the tissues corresponding to the wound area on days 0, 3, 5, 7, and 10. Skin corresponding to the wound area was weighed and normalized to 100 mg of tissue per 2,000 μL (2 mL) of phosphate buffered saline. The wound macerate was diluted in this solution using the serial dilution technique at a ratio of 1:1,000. Then, 100 μL of this solution was plated onto Petri dishes containing cetrimide agar, a microorganism culture medium selective for the isolation of P. aeruginosa in biological samples of animal origin,-1 of tissue.The counterevidence of the presence of -1 of tissue and number of leukocytes per mL of blood) were expressed as mean ± standard error of the mean.For the evaluation of clinical signs of sepsis in the animals, the techniques of liver tissue macerate culture were used at three, five and seven days and total and differential leukocyte counts at days 0, 3, 5, 7 and 10 after the induction of local infection in the wounds. Liver tissue was weighed and normalized to 100 mg of tissue to 1,000 μL (1 mL) of phosphate buffered saline. The techniques for maceration, dilution, and culture of liver tissue were applied identically to the procedures described before for wound culture. The white blood cell count was evaluated by collecting blood from the mouse’s tail, with 5 μL of blood being considered for the total white blood cell count and 5 μL for the smear on a glass slide for the differential cell count. The results obtained  .The survival curve of the animals was determined using the Kaplan–Meier method to estimate the probability of survival at various time intervals. The log-rank test (Mantel–Cox) was used to compare survival curves between both groups.For calculation purposes, the mean area ± standard error of the mean of the wounds at all experimental times was used.Statistical analyses were performed in GraphPad Prism software version 6.0, and results are represented as mean ± standard error of the mean. Values of p < 0.05 were considered significant. For comparisons between two groups over time, two-way analysis of variance (ANOVA) was used, followed by Tukey’s multiple comparisons test with the purpose of checking the interaction between the dependent variables over time. For comparisons between three or more groups, one-way ANOVA was used, followed by Tukey’s multiple comparisons test in order to check the interaction between the independent variables over time.The evaluation of animal survival after wound dressing and induction of infection detected no statistically significant difference between the two tested groups .ni = 37 animals) and seven deaths in the Pa group  throughout the experimental follow-up. These numbers, when compared to the n initial (ni) applied for each group, equate to a mortality percentage of 21.62% in the Pbs group and 16.67% in the Pa group.There were no statistical differences in the percentage of survival between the two groups evaluated (p = 0.5742). There were animal losses in both groups, totaling eigth deaths in the Pbs group  on D5 and 7.67 mm2 (± 0.35 SEM) on D7. The Pbs group had a mean area of 7.36 mm2 (± 0.29 SEM) and 5.01 mm2 (± 0.29 SEM) on D5 and D7, respectively.The mean percentage of wound closure in the Pa group was 43.40% (± 2.61 scanning electron microscope–SEM) at D5 and 62.48% (± 1.67 SEM) at D7. In the Pbs group, this percentage reached 64.64% (± 1.75 SEM) on D5 and 73.96% (± 1.51 SEM) on D7. In the wound area analysis, it was observed that the Pa group had a mean wound area of 12.13 mmThe clinical-ponderal follow-up detected no statistically significant differences between the Pbs and Pa groups regarding the animals’ gross weight . HoweverP. aeruginosa (CFU·g-1) in the tissue corresponding to the wound area at D3, D5, D7 and D10 and a low amount of these microorganisms in the Pbs group at D5, D7 and D10 . There was also a marked reduction in the number of these cells at D5 in both groups studied with a return to levels similar to the baseline level (D0) at D10  at D10 .It was observed that the lymphocytes showed significant reduction in the number of circulating cells on D3, D5 and D7 when compared to D0. However, on D10 of the experiment, these cells return to values close to baseline in both groups evaluated . As well#Pbs vs. Pa in the graph. The results were expressed as the mean ± scanning electron microscope; *p < 0.05.Pbs: control group; Pa: intervention or infected group; P. aeruginosa in its planktonic form , it was not possible to identify the presence of bacterial biofilm or nic form .Some characteristic and well-defined cellular structures were identified in the tissue corresponding to the wound area, such as the presence of collagen fibers, immune system cells, the presence of nerves, blood vessels, and cells in the process of apoptosis .Among the observed characteristics, it is noteworthy that the deposition of collagen fibers was more prominent in the Pa group when compared to the Pbs group .P. aeruginosa in the wound region  model by SEM.The evaluation of the wound samples by TEM did not allow the identification of bacterial biofilm. No bacteria were identified in their planktonic form. The same methodology was applied in a study by other authors-1) was considered as the proof that biofilm was formed in the wound bed. In the publication, there is no information that allows the presence of biofilm and how its structural identification was performedOther researchers have devoted themselves to the induction and formation of the biofilm in murine,The balance between collagen synthesis and degradation occurs around four weeks after the injury, initiating the maturation phase of these fibers, characterized by the replacement of type III collagen by type I collagen, which can last for months or even yearsThe presence of cells such as fibroblasts, eosinophils, and neutrophils with scattered electrodense granules in the cytoplasm and cells with vacuoles containing these granules well delimited within the structure of the vacuoles were suggestive findings that the samples evaluated were in the inflammatory and proliferative phase of the healing processStaphylococcus aureus and P. aeruginosaP. aeruginosa as a biofilm inducing source.The most studied microorganisms associated with wound infection are in-vitro and in-vivo nonmammalian surrogate models, they continue to be widely used, revealing important information about the physiology and treatment of biofilms,Despite the limitations of in-vitro research models include the failures related to reproducing the host environment and the ethical issues surrounding the use of animals in in-vivoPublications present a growing body of evidence suggesting that bacterial biofilms represent an important mainstay in the pathogenesis of chronic woundsIn the present study, the delay in the wound healing process in the Pa group at five and seven days also coincided with the increased bacterial load observed for this same period in the wound culture evaluation. This is different from what occurred in the study evaluating the percentage of epithelialization of partial thickness porcine wounds,,,,,Increased bacterial load is considered one of the causes of chronicity of skin lesions, especially when biofilm formation occurs,,,,,,,,,Researchers have devoted themselves to discussing the microbiota of wounds, according to the classification into chronicP. aeruginosa to induce infection in the wound model adopted in this research is based on the fact that it is one of the main biofilm-forming bacterial microorganisms. From this perspective, some authors point out that the virulence of P. aeruginosa is controlled by a highly complex signaling network involving everything from natural resistance to antimicrobials, to the expression of extracellular appendagesThe choice of The virulence of biofilms is associated with the type of microorganism involved in their formation-,,In this sense, for the clinical evaluation of biofilm in wounds, some authors advocate the characteristic presence on the wound surface: shiny, translucent, and viscous filmRegarding the variation in body weight of the animals over the days, a significant difference was observed between the Pbs and Pa groups at the 5-day time point. Such a fact allows to infer that anesthetic-surgical trauma in conjunction with high bacterial load may interfere with the healing process and weight recovery, contributing to wound chronicity. A finding corroborated by another study, whose authorsThese data support the hypothesis that patients with chronic wound infection may develop persistent weight loss, since there is increased metabolism and reports of inappetence. However, this hypothesis is not clear and requires further studies to be proven. As a way to implement research in this regard, it is suggested that the systematic evaluation of weight variation be included in the anamnesis and care processes of patients with chronic wounds, considering that these components are directly related to the healing process. The findings can be associated with the most requested laboratory tests during the control and clinical follow-up of patients in the health services.The data from the global and differential quantification of leukocytes indicate that in the acute wounds of healthy mice, even considering the bacterial load that was applied to the wounds, they are able to debulk the inflammatory process, preventing the onset of chronicity. However, this result is not confirmed for the wound assessment of patients seen in the various health care services. The chronicity of these wounds, especially venous ulcers, is directly related to the persistence or exacerbation of the inflammatory phase,-Mature bacterial biofilms are capable of modulating host immune response by reducing or inhibiting phagocytosis by immune system cells, antimicrobial resistance; production and secretion of toxins capable of promoting a persistent hypoxic and inflammatory microenvironment in the woundin-vivo studies in the animal model relates to the lack of discussion in the literature surrounding the mortality rate of animals after wound infection with pathogenic microorganisms.When searching for answers in the literature to explain the findings of this study, one came across the scarcity of publications covering the standardization of wound models with biofilm. Such a gap may delay the construction of robust knowledge on the subject. Another limitation observed in the evaluation of the This study allowed us to establish the infection induction technique and the safe bacterial load to induce local wound infection while keeping the animal safe. However, it was not possible to prove the presence of biofilm by means of TEM, making the model limited for product evaluation in biofilm removal. The lack of confirmation of the presence of biofilm in the wound urges the researchers to continue the study for further adjustments.The divergences between the findings of the studies reinforce the need to review the preparation and processing technique of the wound/skin samples for TEM or require the association of other ancillary techniques for the ultrastructural identification of biofilms. The TEM evaluation of the samples allowed us to identify some characteristics in the cellular structures corresponding to the wound area, for example, the presence of collagen fibers, immune system cells, the presence of nerves, blood vessels, and cells in the process of apoptosis. Among these observed characteristics, the presence of collagen fibers and cells containing electrodense granules stood out.Reflecting on the results obtained in this study, we have as expectations for the next phase of the research the hypothesis of evaluating the application of a reinforcement of the bacterial load to ensure the maintenance of infection and/or colonization of the wounds by biofilm for a longer period of time, in order to implement the testing of products used in the treatment of infected wounds with biofilm. This condition is necessary, considering that the adopted wound model, regardless of the bacterial load applied, leads to wound closure between the 10th and 14th day after surgical trauma.In this sense, the research intends to review the standard fixation technique employed in the preparation of skin samples in this phase of the study, aiming to search for some biomarker that facilitates the identification of biofilm microcolonies in the wound, as well as admits the possibility of associating other sample preparation techniques such as cryofixation and rapid freezing, immunohistochemistry techniques and fluorescence microscopy, for example, that may favor the demarcation of the specific wound site to be evaluated by TEM.4 CFU·mL-1 was able to slow down the healing process, simulating critical colonization in excisional wounds of mice, as well as being safe to ensure the survival of animals throughout the experimental design.The results obtained confirm that the proposed infected wound model with bacterial load of 10The point infection induction model was less aggressive compared to the biofilm transfer model employed in other studies.P. aeruginosa in the wound tissue at D5 and D7, when associated with the slowing of the healing process in the animals in the Pa is a strong indication of colonization of the wounds by P. aeruginosa. However, the evaluation by means of TEM did not detect the presence of biofilm or Pseudomonas in its planktonic form in the investigated wounds. The findings raise questions about the understanding of the ease of formation and the high occurrence of biofilm in chronic wounds.The recovery of The results confirm the need for continuation of this study for adjustments in the biofilm infected wound model and improvement of its detection techniques.


In order to explore the mechanical modification effect of diatomite on coastal cement soil at the age of 7 days, based on coastal cement soil with cement content of 5 % (mass fraction), diatomite of 0 %, 5 %, 10 %, 15 % and 20% (mass fraction) was mixed for modification. Through the unconfined compressive strength test, the triaxial unconsolidated undrained test, backscattered electron imaging (BSE), and energy-dispersive spectroscopy (EDS) technology, the influence of diatomite content and confining pressure on the peak strength of modified coastal cement soil was explored. The empirical formula between the peak strength of the DE specimen and the content of diatomite and confining pressure was established by curve fitting, and the fitting effect was ideal. When diatomite was mixed with coastal cement soil, the optimal dosage of diatomite was 5% from the perspective of mechanical properties and economic benefits of the maximum growth rate of compression and shear. The unconfined compressive strength test showed that the peak strength and elastic modulus of the modified coastal cement soil with 5% diatomite content were 37% and 57% higher than those of cement soil, respectively. The triaxial unconsolidated undrained test showed that the internal friction angle of the modified coastal cement soil was stable at about 30°, and cohesion of DE-5, DE-10, DE-15, and DE-20 increased by 28%, 48%, 78%, and 97%, respectively, compared to cement soil. The microscopic test found that the pore distribution of modified coastal cement soil is closely related to the strength change. The results show that the addition of diatomite can effectively improve the mechanical properties of soil-cement.Diatomite is a non-metallic mineral resource rich in SiO Coastal soft soil is widely distributed in the world. Land subsidence caused by high water content, large pores, and low strength of soft soil hinders the development of coastal cities ,2. UneveBecause cement can effectively improve soil properties in terms of strength, plasticity, and stiffness, many scholars have applied cement as a curing agent to improve soil that is not suitable for engineering construction. Ribeiro et al.  carried 2, which has volcanic ash activity and is suitable for replacing some cementing materials. Moreover, the pH of diatomite is neutral, and the incorporation of soil has little effect on the pH of soil. Sardemir et al. [To promote cement soil strength stability and alleviate environmental pollution, natural materials can be used to modify cement soil. Studies have found that diatomite can improve the mechanical properties of cement-based materials ,13,14. Dr et al.  found thr et al.  studied r et al. . In viewIn summary, in this paper, diatomite was used to modify coastal cement soil, and the influence of diatomite on the mechanical properties of coastal cement soil was discussed through the unconfined compressive strength test and the triaxial unconsolidated undrained test. The mechanism underlying diatomite-induced improvement of the mechanical properties of coastal cement soil was studied through backscattered electron imaging (BSE) and energy-dispersive spectroscopy (EDS) technology, which provided a reference for the modification application of coastal cement soil.3 was purchased from Linjiang Dayuan Diatomite New Materials Ecological Environmental Protection Technology Co., Ltd. . The main chemical composition is shown in The raw materials used in the experiment were cement, diatomaceous earth, and coastal soft soil. The soil used in the experiment was collected from the expansion project of the Shaoxing University of Arts and Sciences in Shaoxing City, Zhejiang Province. The region is located in the western part of Ningshao Plain, where marine sedimentary soft soil layers are widely distributed. The main physical parameters of the soil are shown in To study the influence of different diatomite dosages on the mechanical properties of coastal cement soil, the diatomite dosages were preliminarily set at 0%, 5%, 10%, 15%, and 20%. According to the standard for the geotechnical testing method (GB/T50123-2019), the ring tool method was used to measure the sample density, as shown in dC is the diatomite content, cC is the cement content, and wC is the water content. The amounts of all these materials are mass fractions, and the unit is percentage (%). dM is the mass of diatomite, cM is the mass of cement, sM is the dry soil mass of soft coastal soil, wM is the mass of water, and the material unit is grams (g). The test scheme is shown in x, DE represents diatomite-modified coastal cement soil and x represents the diatomite incorporation percentage. The determination of cement weight mainly depends on two aspects: On the one hand, the cement and soil content in similar projects in the Shaoxing area of Zhejiang Province is about 3–8% [Based on the preliminary test, the samples were finally divided into five groups, with five specimens in each group. The amounts of diatomite, cement, and water were determined according to Equations (1)–(3).out 3–8% ,27; on tout 3–8% .(1)The coastal soft soil was baked in an oven at 105 °C for 24 h, as shown in (2)According to the experimental design requirements, the corresponding masses of cement and diatomite were weighed and added to the coastal soft soil with a particle size under 2 mm after screening, as shown in (3)A cushion block was put under the mold, filter paper was put on the cushion block, and a certain amount of mixture was taken with a funnel into the mold three times and evenly inserted, as shown in (4)The mold filled with the mixture and the upper and lower cushion blocks were placed together on the upper part of the bearing plate of the 5t jack in the reaction frame, and the jack was shaken at a constant speed until the upper and lower cushion blocks were pressed into the mold, as shown in (5)After specimen preparation, the specimen was put into a standard curing box for 7 days, as shown in According to the Geotechnical Test Method Standard (GB/T 50123-2019) , the diaThe unconfined compressive strength (UCS) test equipment included the TKA-WCY-1F automatic unconfined compressive test system produced by Nanjing Techao Technology Co., Ltd., , and the test shear speed was set to 1 mm/min. The maximum axial load the UCS tester can withstand is 10 KN, the instrument accuracy is 1 N, and the sensor accuracy is 0.1%. The tests were stopped when the strain reached 8%. Each test was repeated five times, and the average values were used for subsequent analyses.The instrument used in the triaxial unconsolidated undrained (UU) test was the TKA-TTS-3S automatic triaxial apparatus produced by Nanjing Tekao Technology Co., Ltd. The coastal cement soil specimens with different proportions of diatomite were tested under confining pressures of 100 kPa, 200 kPa, 300 kPa, and 400 kPa. The maximum axial load that the UU tester can withstand is 10 KN, the instrument accuracy is 0.1 N, and the sensor accuracy is 0.1%. The tests were terminated when the stress–strain curve stabilized or the axial strain reached 15%.BSE and EDS were performed, as per previous research by Uzarowicz . The BSEThe results obtained by testing only one sample were not representative and reproducible because of the contingency of the test. Testing errors can be reduced by multiple tests on samples, so five parallel tests were carried out on the same group of samples in this paper. At the same time, to reduce the data discretization caused by test errors, the weighted average was used to obtain the normalized curve of the five groups of test data after normalization . Figure 2 in diatomite. This active SiO2 can react with the cement hydration product Ca(OH)2 to generate hydrated calcium silicate gel (C-S-H), and C-S-H has strong cementation, thus improving the compressive strength of coastal cement soil [The increase in the strength of coastal cement soil mixed with diatomite is mainly due to the large amount of active SiOent soil . With thent soil .The elastic modulus is an index to measure the difficulty in the elastic deformation of soil . The larIn Equation (4), 1 represents the major principal stress and σ3 represents the minor principal stress.Taking the peak value of the deviatoric stress as the failure point, the normal stress σ as the abscissa, and the shear stress τ as the ordinate, the strength envelope of the specimen can be drawn . On the From the envelope of the shear strength, the shear strength parameters c and φ and the shear strength formula of the specimens with different diatomite contents can be obtained, as shown in Analysis of the peak strength of the specimen can help to gain a better understanding of the shear failure resistance of the specimen. It can be seen from In conclusion, there is a close relationship between the peak intensity and the content of diatomite and confining pressure. To further explore the relationship between the peak strength (PS) of diatomite-modified coastal marine soil and the diatomite content (D) and confining pressure (CP), a binary first-order polynomial was used to determine the relationship between DE-0 and DE-5. The measured data of DE-10 and DE-15 under 100 kPa, 200 kPa, 300 kPa, and 400 kPa confining pressures were fitted, and the empirical formula of the following Equation (5) was obtained:2) was 0.96, indicating that the model has a good degree of fit. The measured diatomite content and confining pressure were substituted into the empirical formula, and the fitted value was compared with the measured value. The measured value was both above and below the predicted value. This empirical formula was used to predict the peak strength of the specimen under different confining pressures when the diatomite content was 20%, as shown in The fitting accuracy (R2 in diatomite and Ca(OH)2 produced by cement hydration, resulting in flocculent and flake-like cementitious materials. The energy spectrum test of the cemented part in the microstructure of DE-5 showed that the flocculent product was C-S-H, as shown in To understand the effect of diatomite modification on coastal marine soil, BSE tests were carried out on coastal marine soils with different dosages of diatomite, and the test results are shown in The microscopic pore structure in the BSE images of coastal marine soil with different amounts of diatomite was analyzed by the image processing software Image-Pro Plus. The image is binarized and thresholded, the gray value of the image is adjusted to separate the particles in the image from the background, and the image is converted into a black image, where the black areas represent holes . By calc(1)The stress–strain curve of diatomite mixed with coastal seawater is softened. This softening trend is more pronounced in the triaxial unconsolidated undrained test than in the unconfined compressive strength test. With the same content of diatomite, the peak strength increases continuously with the increase in confining pressure.(2)The peak stress of coastal marine soil increases with the increase in diatomite content. When the content of diatomite is 5%, the amount of its strength increases most under different confining pressures. Under confining pressures of 0 kPa, 100 kPa, 200 kPa, 300 kPa, and 400 kPa, the strength of DE-5 increased by 37%, 25%, 20%, 18%, and 17%, respectively, compared to DE-0. An empirical formula of peak strength related to confining pressure and diatomite content was established, and the error of the formula was controlled within 10%, which has certain practical significance in engineering.(3)With the addition of diatomite, the elastic modulus, internal friction angle, and cohesion of the specimens were continuously enhanced. Unconfined compressive strength tests yielded at least a 9% increase in the elastic modulus. In addition, the growth law of elastic modulus is similar to that of compressive strength. From the triaxial unconsolidated undrained test, the internal friction angle was basically stable at about 30° after the addition of 5%, 10%, 15%, and 20% diatomite. The cohesion was 28%, 48%, 78%, and 97% higher, respectively, than that of cement soil, respectively.(4)The incorporation of diatomite produces a large number of flocculent and flake-like cementitious materials inside the soil, which are the product of a pozzolanic reaction and can play a role in curing coastal soft soil. In addition, the quantitative analysis of the microscopic pore area shows that with the increase in diatomite content, the porosity decreases continuously, and the maximum decrease in porosity is 20%. The results of the ultimate compressive strength test are basically the same.Modification of coastal soft soil with diatomite and cement can improve its mechanical properties so that the modified coastal soft soil can be used in road engineering and realize the effective use of coastal soft soil. In this paper, the effects of diatomite on the strength, deformation, and shear properties of coastal marine soil were studied by the unconfined compressive strength test and the triaxial unconsolidated undrained test. In addition, the microscopic mechanism was analyzed using BSE and EDS. The main conclusions are as follows:In this paper, the mechanical properties of coastal cement soil with diatomite at 7 days of age were studied, and the effect of diatomite at 28 days of age on the mechanical properties of coastal cement soil still needs to be further studied. The mechanical tests mainly include the unconfined compression test and the triaxial unconsolidated undrainage test, which can be supplemented by the California load-bearing ratio test and the dynamic triaxial test to further analyze the changes in the mechanical properties of coastal cement soil after diatomite modification. At the same time, the proctor method can be improved for subsequent testing to further understand how the presence of diatoms affects the optimal maximum density–moisture content relationship.


This study examines the extent of scientific publications and patents in pathology and forensic medicine globally and the citation relationship between them from 2011 to 2020, indexed in the Scopus database. In this scientometric study, data were extracted from the SciVal citation database. Search feature and library study method and annual growth rate, relative growth rate, and linear model were used to retrieve and analyze the data. The scientometric indicators included the number of publications and patents of the university in collaboration with industry, the number of articles cited by patents, the number of patents cited by articles, the average number of patents cited by articles, and the number of articles cited.2 = 0.982, which is inverse and negative. The data set of articles and citations was suitable for polynomial (R2 = .994), linear (R2= .982) and exponential (R2 = .887) models. The results showed a poor collaboration between academia and industry in pathology and forensic Medicine, and North America is the busiest region in this field. The average growth of patents based on articles, the number of articles mentioned in patents, citations to patents, and the average number of patents of an institute in the articles of that institute have a positive exponential relationship. Based on the linear model, the relationship between articles and citations equals RThe research process of pathology and forensic medicine is inappropriate, and the citation relationships between articles and patents in this field are weak. Strengthening the link between academia and industry in pathology and forensic medicine can strengthen research in this field. Today, the trend towards the scientific and technological policy is increasing. The ability to generate scientific and technological knowledge (S&T) and translate it into new products or processes is a key tool for economic growth and development. It plays an increasingly important role in the economic develop-pment of countries worldwide . ScientiResearch in medicine has received much attention due to its economic profitability among the necessary research fields, as medical research is related to human longevity and health. One of the disciplines of medicine as an important bridge between the basic and clinical sciences of biomedicine is the field of pathology and forensic Medicine, which is helpful in diagnosis, treatment, and prevention . Patholoet al., measuring citations in more than 8,000 biomolecular patents, showed that citations in the biomedical literature and patents have a different pattern , defined as the percentage change in the number of publications over a period of 1 year, was calculated based on the following equation: AGR= [/Beginning Value] * 100 .Growth of publications, patents, citations, and growth rate indicators were analyzed based on two scientometric parameters, namely, the relative growth rate (RGR) and doubling time (DT). RGR is the increase in the number of publications, citations, and patents per unit of time, and it is calculated using the formula RGR :  (1)Where,RGR = N1 and N2 = Loge (are the cumulative numbers of publications for years T2 and T1)T1 = The unit of the initial time T2 = The unit of the final timeSince the current study calculates the RGR for successive years and given that T2, T1 = 1, Eq. (1) can be simplified as Eq. (2):(2)2) – LN (N1). RGR= LN (3)Growth Model2 is to the number 1, the trend follows the linear trend, and the closer it is to the number 0, it gets away from the linear trend  This means that the number of citations has decreased with the increase of articles and shows a negative and inverse relationship. The annual Fit Curve of citation to articles from 2011 to 2021 based on 2=0.982). The existing data fits the Polynomial Model (R2=.994), Linear Model (R2=0.982), Exponential Model (R2=.887), Logistic Model (R2=0.826), and Power Model (R2=0.659) well because the value of their R2 was close to 1 declared that they have no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.This study was supported by the National Institute for Medical Research Development (NIMAD), Islamic Republic of Iran.


We investigated changes in the activity of antioxidant paraoxonase-1 (PON1) in patients with prostate cancer (PCa) undergoing radiotherapy (RT), as well as the relationship of the PON1 activity with the degree of PCa advancement. We included 84 men with PCa. Blood samples were obtained before irradiation and after the completion of RT. The control group was composed of 60 healthy men. There was no significant difference in the PON1 activity between the control group and patients pre-radiotherapy. Irradiation was associated with a significant decrease in the PON1 activity; thus, it could be a measure of the efficacy of RT. No significant correlations between the PON1 activity and Gleason score, prostate volume, BMI (body mass index), or adipose tissue thickness were found. However, there was a positive correlation between the PON1 activity and the PSA concentration in the group of PCa patients. Currently, there are two basic methods for the radical treatment of PCa confined to the organ: surgery  and RT. RT can be carried out using two methods: external beam radiation therapy (EBRT) or intratissue irradiation–brachytherapy (BT); it is also possible to combine both methods (BT + EBRT). Brachytherapy uses radioactive sources implanted in the prostate parenchyma in the immediate vicinity of the tumor: permanent low-dose rate (LDR) brachytherapy using isotopes of iodine, palladium, and cesium  or temporary high-dose rate (HDR) brachytherapy using the iridium isotope Ir-192 [The basic criteria taken into account when qualifying patients for PCa brachytherapy are the PSA (prostate-specific antigen) concentration, tumor differentiation according to the Gleason classification, and TNM clinical stage ,4,5. PatHDR (high-dose rate) brachytherapy is a method of PCa treatment with an effectiveness that has been confirmed in many studies, as well as a five-year biochemical recurrence-free survival rate of 90, 85, and 65%, respectively, for low-, medium-, and high-risk groups .Reactive oxygen species (ROS) may form in the body under the influence of exogenous factors, such as high temperature, ionizing radiation, tobacco smoke, alcohol, and pesticides, and endogenously mainly in the mitochondrial respiratory chain, as well as in reactions involving oxidoreductases, phagocyte activation, purine nucleotide metabolism, and microsomal hydroxylation cycle (cytochrome P-450) . Damage Living organisms have intracellular mechanisms that maintain the reduction and oxidation potential —a set of enzymatic antioxidants that also includes repair enzymes, e.g., by reducing the products of lipid peroxidation such as type 1 paraoxonase (PON1). The activity of PON1 in plasma shows significant differences between individuals, even several times ,14,15,16The initial study of PONs was related to the toxicological aspects of this enzyme due to the fact of their ability to detoxify organophosphate compounds. More recent studies have demonstrated a correlation of the PON activity with various cardiovascular diseases, such as diabetes, neurological disorders, and cancers ,19. ThisThe severity of oxidative stress depends on the rate of the formation of free radicals and the rate of their removal. PON1 is an element of the so-called third line of defense—mechanisms that remove the products of free radical reactions by repairing or eliminating damaged particles.In recent years, the serum PON1 activity has been reported to be reduced in several types of malignancies, such as lung cancer, gastrointestinal cancer, breast and prostate cancer, bladder cancer, central nervous system tumors, non-Hodgkin’s lymphoma, and acute lymphoblastic lymphoma ,24. MitoThe aim of this study was to investigate the changes in the PON1 activity under the influence of ionizing radiation, as well as the relationship between the serum PON1 activity and the degree of advancement of PCa in patients undergoing radiotherapy. We also conducted an analysis of the possible relationships between the PON1 activity and known risk factors for PCa recurrence—PSA and Gleason score, as well as prostate volume, body mass index (BMI), and adipose tissue thickness.Eighty-four men  undergoing RT for prostate cancer in 2005–2010 at the Department of Brachytherapy in our hospital were included in the study. All patients had biopsy-proven prostate cancer  and PSA determination. The stage (TNM) was determined according to the American Joint Committee on Cancer (AJCC) TNM classification from 2002 . All patThe control group consisted of 60 healthy men  in whom the PSA concentration and PON1 activity were determined. The mean age in this group was 63.0 ± 13.2 years. Both in the study and in the control group, a similar frequency of comorbidities typical for age was observed: arterial hypertension, type 2 diabetes, and coronary artery disease. The patients with clinical stage T1-T2bN0M0, a PSA below 10 ng/mL, and a Gleason score not higher than 6, qualified for HDR brachytherapy alone. Other patients were qualified for combined BT with EBRT. Due to the small number of patients studied, we did not distinguish patients who underwent only BT from those who underwent BT + EBRT in the analysis. Forty-three patients received hormone therapy together with radiation treatment. The radiation schedule was EBRT 46 Gy in 23 fractions (2 Gy/day) combined with two 10 Gy HDR brachytherapy fractions .2, and the activities are expressed as IU/l [Blood samples were obtained prior to irradiation, after the completion of irradiation, and 7–8 weeks later. The sera were stored at −80 °C until the biochemical analysis, however, no longer than two months. The serum PON1 activity was determined, as we previously described , accordi as IU/l ,35.The study was realized in accordance with the Declaration of Helsinki and approved by the local Ethics Committee (KB/424/2005 with an annex). All participants signed written consent.n > 50); the parametric test for two structure indicators in order to verify the hypothesis that the frequencies of the distinguished cases in the compared groups did not differ significantly; and Snedecor’s F-test to verify the hypothesis of the homogeneity of the variance in the two compared groups. Parametric tests were applied to compare the mean values. In the case of the homogeneity of the variance in the compared groups, the hypothesis of the equality of the means was verified using the student’s t-test. When this condition was not met, the Cochran–Cox test was used. The student’s t-test for dependent variables (paired data) or the Wilcoxon test were used when the assumptions of the student’s t-test were not met. The nonparametric Shapiro–Wilk test was applied to verify the hypotheses regarding the normality of the distributions of the examined features. If the hypothesis of normal distribution was rejected, the nonparametric Mann–Whitney U test was used to compare the groups. At p < 0.05, the difference was considered statistically significant.The study results were processed using the STATISTICA 8.0 program and are presented as the mean with standard deviations. The statistical analysis was carried out using the Z-test based on a normal distribution to compare the means of two sufficiently large groups  had T1-T2 cancer, and five patients had a T3 disease. A low histopathological stage (Gleason score < 7) was found in 60% of patients. The mean pretreatment PSA was 12.53 ng/mL (2–88 ng/mL), and the mean prostate volume was 34.87 mL (10–64 mL). Fifty-one percent of the patients (n = 43) received neoadjuvant hormone therapy. The main clinical characteristics of the patients are presented in p = 0.013) than in the control group, and the PSA level was significantly higher .Ninety-four percent of the patients (p = 0.006) and 2 months after the end of RT  compared to the activity before the start of treatment. The difference between the PON1 activity immediately after BT and after the next 2 months was 5% and was not statistically significant (p = 0.542).p = 0.064) .= 0.064) . There wp = 0.513 and p = 0.651, respectively). In the group of patients not receiving hormonal therapy, a statistically significant decrease in the PON1 activity was observed immediately after irradiation  and 2 months after the end of RT  compared to the activity before the start of treatment  is a typical age for patients undergoing HDR and EBRT brachytherapy ,38,39. Tp = 0.99) suggests that the PON1 activity in patients with PCa and in the population of healthy men was very similar. It can be assumed that PCa does not have the same mechanism of deregulation of PON1 activity as in other cancers.The first measurement of the PON1 activity in the study group was made before the start of treatment. The comparison of this parameter in the control group with the first result obtained in the study group can be treated as a comparison of the population of healthy men with the population of patients with PCa, without the influence of RT, a factor that may potentially cause a change in the PON1 activity. The results of this comparison did not show statistically significant differences in the PON1 activity, and a small difference  was not reached. However, this may be due to the small size of the study group. On the other hand, reports have been published indicating the existence of a negative correlation between the BMI and PON1 activity [No papers examining the relationship between prostate volume and PON1 activity have been found in the literature. The obtained results do not clearly indicate the existence of such a relationship; the significance level of activity . No suchactivity .p < 0.05 (p = 0.061), but the correlation was determined to be positive. The measurement of the thickness of the adipose tissue in MR is a parameter that better reflects the amount of adipose tissue than the commonly used BMI, which is influenced by many factors. If the lack of statistical significance resulted only from too small a sample size and the observed positive correlation exists, it would be in contradiction with the described negative correlation between the BMI and PON1 activity.It is surprising that the level of significance of the correlation between the thickness of the adipose tissue at the level of the umbilicus and PON1 activity approached the limit value of PSA is a kallikrein produced by both normal prostate epithelial cells and prostate cancer cells. An increase in the PSA concentration may, therefore, be associated with cancer , as well as an increase in the mass of the gland in the course of BPH or prostatitis. The serum PSA concentration in patients with locally advanced PCa depends mainly on the advancement of the disease and the related change in the histological structure of the prostate, as well as on the biology of the tumor. The less differentiated the tumor cells, the more malignant the tumor; these cells produce less PSA . TherefoThere was no significant relationship between the PON1 activity and the Gleason score, which is related to the histopathological differentiation of the tumor. The obtained results do not allow for a full explain of the cause of the observed correlation between the PON1 activity and PSA concentration in the study group.One of the limitations of the study was the small size of the patient subgroups. For this reason, not all patients underwent a second (2 months after the start of irradiation) and a third (after another 2 months) determination of the PON1 activity. Moreover, the correlations between the PON1 activity and BMI, adipose tissue thickness, prostate volume, PSA concentration, and Gleason score were assessed, only taking into account the parameters determined before the start of RT. After the treatment was completed, a series of follow-up visits to the Radiotherapy Outpatient Clinic was planned, during which only a physical examination and subjective examination were performed, as well as the PSA concentration and PON 1 activity in the serum.In the patients included in the study group, the parameters of lipid metabolism that could potentially affect the PON1 activity were not determined, as these tests are not routinely performed in the observation of patients undergoing brachytherapy for PCa . PON1 isDespite these limitations, we managed to obtain statistically significant differences between the subgroups in terms of the PON1 activity.It would be beneficial if the scope of the performed tests was extended to include further determinations of the PON1 activity after more than 4 months from the start of irradiation, which would allow for the assessment of changes in the PON1 activity in a more distant time after RT and to determine whether and after what time after RT the activity of PON1 normalizes. At the time of designing the experiment, there were no reports on changes in the PON1 activity under the influence of ionizing radiation; it was difficult to predict how long a possible change in the activity of this enzyme might persist after the end of treatment.No differences in the PON1 activity were observed between the patients with PCa and healthy men. Exposure to ionizing radiation during brachytherapy and teleradiotherapy caused a decrease in the PON1 activity. There were no significant correlations between the PON1 activity and Gleason score, prostate volume, BMI, or adipose tissue thickness. However, there was a positive correlation between the PON1 activity and PSA concentration in the group of PCa patients. There is a need to expand preclinical radiobiological studies to understand the role and importance of PON1 in radiotherapy treatment.


Phenotypic variability can be structured according to three interrelated components: developmental stability, morphological integration, and canalization. The cranium presents modular organization, consistent with the principles of morphological integration. In Down syndrome (DS), the most common genetic aneuploidy, the integration of the cranial-vertebral-maxillary complex, remains unknown. This study aimed to analyze whether there are significant relationships between the skull base, atlantoaxial joint, and maxillary-mandibular complex in a study group of 41 individuals with DS and nonsyndromic controls. Twenty-nine measurements were performed on each participant’s cone-beam computed tomography images, which were grouped into three blocks: atlantoaxial dimensions, craniovertebral dimensions, and cephalometric dimensions. With regard to the association between blocks, we found no significant relationship in the DS group. However, we confirmed a statistically significant correlation between all blocks of variables in the controls. In conclusion, these results confirm a very poor morphological integration of the cranial-cervical-maxillary complex in individuals with DS. This finding reinforces the proposal that gene overload enhances canalization, which could potentially affect the outcomes of certain orthopedic and surgical procedures.p < 0.001). The highest discriminative capacity to identify controls and patients with DS was obtained with the cephalometric dimensions (87.5%). With regard to the association between blocks (two-by-two measurements), we found no significant relationship in the DS group. However, we confirmed a statistically significant correlation between all pairs of blocks of variables in the controls, especially between the atlantoaxial and cephalometric dimensions (p < 0.001) and between the craniovertebral and cephalometric dimensions (p < 0.001). Conclusions: Our results confirm a very poor morphological integration of the cranial-cervical-maxillary complex in individuals with DS. This finding reinforces the proposal that gene overload enhances the channeling process.Background: Morphological integration refers to the tendency of anatomical structures to show correlated variations because they develop in response to shared developmental processes or function in concert with other structures. The objective of this study was to determine the relationships between the dimensions of different cranial-cervical-facial structures in patients with Down syndrome (DS). Methodology: The study group consisted of 41 individuals with DS who had undergone cone-beam computed tomography (CBCT) at the Dental Radiology Unit of the University of Santiago de Compostela (Spain). In the historical archive of this same unit, 41 CBCTs belonging to individuals with no known systemic disorders or severe malformations of the maxillofacial region were selected, forming an age and sex-matched control group. Twenty-nine measurements were performed on each participant’s CBCT images, which were grouped into three blocks: atlantoaxial dimensions, craniovertebral dimensions and cephalometric dimensions. To determine whether there were significant differences between the dimensions obtained in the DS and control groups, we applied multiple analysis of variance and linear discriminant analysis tests. The analysis of the association between blocks (in pairs) was performed with the canonical correlation analysis test. Results: The dimensions evaluated in the three blocks of variables of individuals with DS differ significantly from those of nonsyndromic controls ( Down syndrome (DS) is a disorder characterized by the presence of an additional chromosome or a part of the same in position 21, which causes a characteristic phenotype, intellectual disability and several physical and medical peculiarities . The pheStability is a property of development that can limit phenotypic variation when faced with random perturbations  that occur during the course of ontogeny, such that a certain phenotype is produced under specific genetic and environmental conditions ,6. When Modularity is an important organizational component in biological systems that describes the differences in the degree of trait integration between and within groups and subgroups of structures and that is manifested at the morphological level . MorpholIn the 1940s, Conrad H. Waddington  employedThe deficient development that characterizes DS also affects the head, which is generally small and has a tendency toward a brachycephalic pattern . The craThis study aimed to analyze whether there are significant relationships between the skull base, atlantoaxial joint and maxillary-mandibular complex in a group of individuals with DS, assuming that these structures behave as modules, given that they share developmental precursors, are located spatially close to each other, participate jointly in various functions and have a common evolutionary history. The null hypothesis is that there is no significant morphological integration between the skull base, atlantoaxial joint and maxillary-mandibular complex.The study group of convenience consisted of 41 individuals with DS  between the ages of 9 and 43 years. The mean age of the female participants was 17.2 ± 5.3 years (range 7–29 years) and that of the male participants was 19.9 ± 8.3 years (range 9–43 years). The mean age of the female participants was 17.2 ± 5.3 years (range 7–29 years) and that of the male participants was 19.9 ± 8.3 years (range 9–43 years). The age distribution of the study group was as follows: 9–15 years, 12 individuals; 16–20 years, 19 individuals; 21–25 years, 4 individuals; 26–30 years, 2 individuals; 31–35 years, 2 individuals; and 36–40 years, 2 individuals. All participants had undergone cone-beam computed tomography (CBCT) within the framework of a previous study conducted in the Faculty of Medicine and Odontology of the University of Santiago de Compostela (Spain).The inclusion criteria were as follows: not having undergone previous orthopedic/orthodontic treatment, not having undergone maxillofacial surgery involving the maxillary bones and having images of the cranial-cervical-facial complex of acceptable quality in the three orthogonal spatial planes. These images should allow for a complete cephalometric tracing that includes the following end points: (1) in the anteroposterior direction, from the anterior nasal spine to the most caudal portion of the occipital lamina, and (2) in the vertical axis, from the basion to at least the base of the axis.Applying the same inclusion criteria, we selected a control group of 41 individuals without systemic disease and without severe maxillofacial bone malformations, paired by sex  and age (the mean age was 16.5 ± 5.7 years (range 8–29 years) for the female participants and 18.8 ± 8.5 years (range 9–43 years) for the male participants) with the study group.The participants  signed an informed consent authorizing the use of the images. The study design was approved by the Ethics Committee of the University of Santiago de Compostela.® cone-beam computed tomography system . The imaging studies were performed by a single operator, following the manufacturer’s instructions, and standardizing the patients’ position. To perform the scanning, the participants were placed in the standing position, with the intermaxillary occlusion in maximum intercuspation and with the following head position: in the sagittal plane, with the Frankfurt plane parallel to the floor , and in the frontal plane, with the vertebral body aligned with the vertical axis.The images were obtained using an i-CAT® Vision 17.1 software  and were exported in DICOM format  to a personal computer with MacBook 27 software . All measurements were performed using the open-source, image-processing software OsiriX .The images were obtained at 120 kVp and 5.0 mA; the voxel size was 0.3 mm, with a field of view of 10–20 cm and an exposure time of 8.9 s. All images were reconstructed using i-CATThe CBCT scans were oriented by aligning the palatal vault with the X axis  and the midpalatal suture with the Y axis . The cursor was then moved within the plane that was the object of the study following the Z axis . The images were analyzed in the sagittal and frontal planes: the sagittal plane was that which crossed the midpoint of the odontoid apophysis and the facial midline; the frontal plane was established based on the highest point of the odontoid apophysis.Twenty-nine measurements grouped into three blocks were performed on each patient . The firTo check the intraexaminer repeatability, a single observer repeated the measurements of 10 randomly selected cases (5 patients with DS and 5 controls) one month after the first measurements, obtaining an intraclass correlation coefficient of 0.94 (95% CI 0.84–0.96) for all evaluated variables. To analyze the interobserver reproducibility, two observers performed all the measurements in 10 other randomly selected cases (5 patients with DS and 5 controls), obtaining an intraclass correlation coefficient of 0.92 (95% CI 0.72–0.99). The lowest values corresponded to variables AA1-L and AA1-R .We conducted an analysis of the differences between the cases and controls to determine whether it was possible to discriminate between the two groups based on the values of the variables for each of the three examined blocks. Basically, we sought to find a linear combination of response variables that maximized the differences between the cases and controls. To this end, we performed a multivariate analysis of variance to assess the presence of intergroup differences in the means and then performed a linear discriminant analysis to obtain the linear combination of variables that maximizes the intergroup discrimination.To analyze the association of the measurements between pairs of blocks of variables , we selected the canonical correlation analysis methodology because this method allows for the sequential extraction of linear combinations of variables  searching for the maximum sample correlation. The objective of the analysis is to obtain the canonical dimensions  and to test for their significance. We used the Pillai–Barlett Trace using the F-approximation to reach this goal. The estimation of the numerator and denominator degrees of freedom of the test takes into account the sample size and the dimension of the blocks (number of variables in each block). The canonical correlation between the sets of items of each dimension was also estimated.The measurements of centralization and dispersion of the atlantoaxial, craniovertebral and cephalometric dimensions in the DS and control groups are detailed in p < 0.001). The craniovertebral dimensions of the DS group were significantly larger than those of the control group (p < 0.001), except for the length of the odontoid apophysis, which was significantly shorter in the DS group (p < 0.001). The cephalometric dimensions of the DS group differed significantly from those of the control group (p < 0.001).The atlantoaxial dimensions of the DS group were significantly smaller than those of the control group  the various measurement blocks , the dimensionality test for the canonical analysis of the DS group shows that none of the six canonical dimensions was statistically significant at the 0.05 level in any of the pairs , which iThis study showed that the atlantoaxial, craniovertebral, and cephalometric dimensions of the individuals with DS differed significantly from those recorded in the nonsyndromic individuals. In contrast to the control group, the three measurement blocks in the DS group were independent of each other.The hypothesis has been suggested that trisomy 21 causes “amplified developmental instability”, which results in increased asymmetry and variability of the phenotypic characteristics ,29. In DFacial morphogenesis requires adequate spatiotemporal deployment of gene products, neural crest cells, and other cells to develop the facial prominences . These pStarbuck et al.  reportedThe proponents of the hypothesis of amplified developmental instability ,37,38 hoHowever, Starbuck et al.  demonstrAnother study published by Starbuck et al. , whose oStarbuck et al.  also fouPritchard and Kola  defendedThis study is not exempt from several limitations that should be considered when interpreting the results. All of the participants underwent a CBCT examination, which could entail a selection bias based on their degree of cooperation , given tThe atlantoaxial, craniovertebral, and cephalometric dimensions of individuals with DS differ significantly from those of nonsyndromic controls. Unlike the general population, the individuals with DS had no statistically significant relationship between these three blocks of dimensions. This confirms that in DS, the cranial-cervical-maxillary morphological integration is very poor, reinforcing the hypothesis of genetic overload to explain the DS phenotype. Additionally, these findings could affect the decision making and the long-term results of certain interventions in this anatomical region, such as maxillofacial orthopedics and orthognathic surgery.


Finally, the fluidity of the polymer solution in the core was analyzed by injection pressure control features. The experimental results show that the polymer solution with a molecular weight of 25 million has the best retention effect in the core flooding experiment and can stay in the dominant channel of the core for a long time to control the water flooding mobility. In rocks with a permeability of 500, 1000, and 2000 mD, subsequent water flooding can expand the swept volume by about 25% compared with polymer flooding. This method can effectively establish the adaptability matching relationship between the polymer molecular weight and the reservoir permeability.In order to study the matching relationship between polymer(HPAM) molecular weight and reservoir permeability, in this paper, the injection performance of polymers with different molecular weights in rock cores with different permeability is studied. Using nuclear magnetic resonance technology combined with conventional core displacement equipment, the change law of the displacement process was analyzed from three aspects of nuclear magnetic resonance  Polymers are used in a wide range between art, structure, outdoor equipment, oil, gas, aerospace, etc. ,2,3. PolThe choice of polymer in oilfield applications needs to match the permeability of the reservoir . If the Nuclear magnetic resonance (NMR) technology is widely used in the determination of fluid properties and rock properties and has the characteristics of speed, accuracy, and non-destructiveness ,13,14. C2T spectrum, core layering, and imaging, and determine the main producing pore range of polymer flooding and water flooding. Then, through imaging and core layering, it is analyzed which part of the polymer plays a role in the core. Finally, compare the differences in injection pressure characteristics. The evaluation method of polymer adaptability is established to provide technical support for the promotion and application of polymer flooding technology.In order to further tap the potential of polymers to enhance oil recovery, the main research object of this paper is the injection performance of polymers in reservoirs with different permeability. Firstly, nuclear magnetic resonance technology is used to monitor and analyze the change law of the core displacement process from three aspects of nuclear magnetic resonance Polymers (HPAM), molecular weight 16 million , molecular weight 19 million , molecular weight 25 million , provided by China Petroleum Exploration and Development Research Institute. Artificial cores , purchased from Beijing Huarui Xincheng Technology Co., Ltd. , The data are shown in The NMR displacement device is mainly composed of a conventional displacement device and a nuclear magnetic resonance analyzer. The MR-dd high-temperature and high-pressure displacement device is produced by Nantong Huaxing Petroleum Instrument Co., Ltd. . The MesoMR23-060H-HTHP core low-field nuclear magnetic analyzer is produced by Shanghai Numai Electronic Technology Co., Ltd. . The physical diagram and flow chart of the low-field NMR displacement device are shown in 1H in water or oil fluid can reflect signals in nuclear magnetic resonance. However, there are pores of different sizes in the rock core, and the water or oil fluid in these pores, due to the change in the size or content of the space, the signals reflected in the nuclear magnetic resonance are also different. The detected signal can accurately reflect the distribution and change in the fluid in the core pores. [In the core displacement experiment, there are mainly two fluids in the core: water and oil (gas flooding is not considered). A large number of atomic nuclei e pores. .2T is used as the abscissa and the signal value as the ordinate, and the distribution of the 2T time can be obtained, that is, the transverse relaxation 2T spectrum curve  represents the total signal value of the liquid in the small pores. The area of the middle peak (2P peak) represents the total signal of the liquid in the mesopores. The area of the right peak (3P peak) represents the total signal value of the liquid in the large pores. Therefore, during the core displacement experiment, by measuring the change in the transverse relaxation curve (2T spectrum) of the 1H-containing proton fluid in the core, the distribution of the 1H-containing fluid in different pores and the change in its content in the core can be obtained.The obtained he pores ,19. FiguThe layered sequence detection technology can divide the core into multiple sections for NMR signal monitoring. In order to study the injection performance characteristics of polymers in cores, a method combining nuclear magnetic resonance technology and conventional core displacement equipment is used. First, select three polymers with different molecular weights , and prepare a 1000 mg/L polymer solution with simulated mineralized water. Secondly, three kinds of cores with different permeability  were selected for core displacement experiments, and the displacement characteristics of polymer solutions with different molecular weights in cores with different seepage flow rates were compared and analyzed. All the core displacement experiments were carried out with a constant flow rate of 0.3 mL/min .(1)The core is dried, and then vacuumed and saturated with deuterium water;(2)2T spectrum curve, layered signal, and imaging of polymer flooding;Inject the prepared polymer solution at a constant flow of 0.3 mL/min until the injection pressure is constant, and obtain the NMR (3)2T spectrum curve, layered signal, and imaging of subsequent water flooding.Continue to inject simulated mineralized water at a constant flow rate of 0.3 mL/min until the injection pressure is constant, and obtain the nuclear magnetic resonance The specific experimental steps are as follows .Main test parameters of nuclear magnetic resonance equipment: magnetic field strength 0.5 T, resonance frequency 21 MHz, probe coil diameter 70 mm; FID sequence parameters: receiver bandwidth SW 125 KHz, recovery time TW 3000 ms, number of sampling points TD 1024, RF coil dead time RFD 0.002, analog gain RG1 20 dB, digital gain DRG1 3, accumulation times NS 16; CPMG sequence parameters: receiver bandwidth SW 200 KHz, preamplifier position PRG 2, recovery time TW 3000 ms, echo time TE 0.3 ms, echo The quantity NE is 8000; the number of In order to ensure that the nuclear magnetic signal has no interference from external factors, in the experiment, the NMR signal detection of polymer flooding and subsequent water flooding was measured under the condition that the pressure at the inlet and outlet ports was atmospheric pressure. Therefore, the injection pressure changes during polymer flooding and subsequent water flooding were monitored from zero.To sum up, in the same permeability core, the injection pressure of a polymer with a molecular weight of 19 million is slightly higher than that of a polymer with a molecular weight of 16 million, while the injection pressure of a polymer with a molecular weight of 25 million is obviously higher than the former. It shows that the injection pressure increases with the increase in molecular weight. In the core flooding experiments of polymers with a molecular weight of 16 million and 19 million, the injection pressure of the subsequent water flooding decreased rapidly, indicating that it is difficult for such polymers to stay in the core for a long time. In the core flooding experiment of polymer with a molecular weight of 25 million, the subsequent water flooding declines slowly, and the final stable pressure is higher, indicating that this polymer can be better retained in the water flooding dominant channel of the core.2T spectrum change curves of polymers with a molecular weight of 16 million during the core flooding process of three different permeability. The red line is the NMR 2T spectrum line measured after polymer injection, and the blue line is the NMR 2T spectrum line measured after the subsequent water flooding  and 3P peak (large pores). The total nuclear magnetic signal value of polymer flooding is 32,851, and the total nuclear magnetic signal value of subsequent water flooding is 36,377. According to the calculation according to Formula (1), subsequent water flooding expands the swept volume by 10.07% on the basis of polymer flooding.I—Sweep volume increase rate, %; SP, SW—NMR 2T spectrum peak area of polymer flooding and subsequent water flooding, dimensionless.2T spectrum change curves of polymers with a molecular weight of 25 million during the core flooding process of three different permeability. In the three core flooding experiments with different permeability, the subsequent water flooding increased the signal value on the basis of polymer flooding, and it was mainly manifested in the P3 peak (large pores), and the signal of the P1 peak  increased slightly. It shows that subsequent water flooding further expands the swept volume on the basis of polymer flooding. Calculated according to Formula (1), among them, in the 500 mD core, the expanded swept volume is 25.36%, in the 1000 mD core, the expanded swept volume is 27.03%, and in the 2000 mD core, the expanded swept volume is 25.06%.2T spectrum curves show that in three different permeability core displacement experiments, polymers with a molecular weight of 16 million and 19 million failed to effectively stay in the water flooding dominant channel of the core, and the subsequent injection water still flows from the channel through which the polymer solution passes. Therefore, subsequent water flooding failed to further expand the swept volume on the basis of polymer flooding. The polymer with a molecular weight of 25 million can stay in the dominant channel of the core for a long time in three different permeability cores, controlling the water flooding mobility, so that the subsequent water flooding can enter the pores that the polymer solution cannot enter, thereby greatly expanding sweep volume.The results of NMR 2T spectrum curve.2T spectrum curve.2T spectrum, NMR layered signal, and imaging), it is possible to more accurately determine the matching adaptability between the molecular weight of the polymer and the permeability of the rock core.Through the injection performance experiments of polymer solutions with different molecular weights in rock cores with different permeability, and analysis from four aspects (injection pressure, NMR 2T spectrum, nuclear magnetic resonance layering signal, and imaging are analyzed, which can accurately characterize the adaptive matching relationship between polymer molecular weight and rock core permeability.Using nuclear magnetic resonance technology, through the injection core experiment of polymer solution, the change characteristics of four aspects of injection pressure, nuclear magnetic resonance As the molecular weight increases, the injection pressure of the three different permeability cores increases accordingly. It is difficult for the polymer solutions with a molecular weight of 16 million and 19 million to stay in the core for a long time, and the subsequent water flooding pressure decreases rapidly. The polymer with a molecular weight of 25 million can stay in the core for a long time and control the water flooding mobility.Among the core flooding experiments of polymers with different molecular weights, the polymer with a molecular weight of 25 million performed the best. In the 500–2000 mD core, the dominant channel of water flooding can be well controlled, and the subsequent water flooding can further enter the pores that the polymer solution cannot reach. Subsequent water flooding can expand the swept volume by about 25% compared with polymer flooding, thereby greatly improving oil recovery.


The exciton states and their influence on the optical absorption spectrum of CdSe and PbS nanoplatelets (NPLs) are considered theoretically in this paper. The problem is discussed in cases of strong, intermediate, and weak size quantization regimes of charge carrier motion in NPLs. For each size quantization regime, the corresponding potential that adequately describes the electron–hole interaction in this mode of space quantization of charge carriers is chosen. The single-particle energy spectra and corresponding wave functions for strong intermediate and weak size quantization regimes have been revealed. The dependence of material parameters on the number of monolayers in the sample has been considered. The related selection rules and the dependence of the absorption coefficient on the frequency and polarization direction of the incident light wave were obtained. The interband transition threshold energy dependencies were obtained for each size quantization regime. The effect of dielectric coefficient mismatch and different models of electron–hole interaction potentials have been studied in CdSe and PbS NPLs. It is also shown that with an increase in the linear dimensions of the structure, the threshold frequency of absorption decreases. The binding energies and absorption coefficient results for NPL with different thicknesses agree with the experimental data. The values of the absorption exciton peaks measured experimentally are close to our calculated values for CdSe and PbS samples. The physical properties of quasi-two-dimensional colloidal semiconductor nanostructures with planar geometry, so-called semiconductor nanoplatelets (NPLs), along with many low-dimensional semiconductors, have also been intensively studied in the last decade mHere iltonian ,46. Laten [γ1,γ2 . In the Z direction for electrons and holes, respectively, and Here The perturbation associated with the light wave will be presented in the following form :(2)V^=emc-speed of light in the vacuum. It is well known that for the sample under the light-wave perturbation, Equation (2) there are two types of possible transition in quasi-2D systems: interband and intraband. We will discuss both transition mechanisms by considering linear absorption in NPLs. The interband transitions are connected with the electron–hole pair generation or annihilation. For the interband absorption coefficient Here, pression :(3)K(ω)=Here Here, erolayer . The absUsing the well-known calculation method  for the In our case, the quantitative criterion for the implementation of the strong quantization regime is the fulfillment of the following condition:X, Y, and Z directions is much greater than the energy of the Coulomb interaction between an electron and a hole [X, Y, Z directions by an infinitely deep rectangular potential, neglecting the Coulomb interaction between an electron and a hole, for the envelope wave functions and the energy spectrum of charge carriers in the CdSe NPL in the corresponding directions, we obtain:From the energy point of view, condition in Equation (7) means that in the material under consideration, the size quantization energy of charge carriers in any of the d a hole ,54,55. AWith the wave functions from Equation (8) for the matrix elements of the interband dipole transitions, we obtain:Here Considering infinitely deep potential well approximation in all three directions However, the results obtained within the framework of this approximation differ significantly from the results of ,49. A moFurthermore, in the case of those of .In the case of intraband–intersubband transitions, it is expedient to separately consider the following three cases of linear polarization of the incident wave: i, f) in the same band and corresponding matrix elements, we obtain, using expression Equation (6), respectively:For the frequencies of transitions between subbands (Consideration of the intraband transitions Equations (13) and (14) under conditions Equation (12) eliminate the mixing of absorption bands in different directions and makes it possible to determine the optical parameters of the sample for each specific size quantization direction.Z-direction are much smaller than the Bohr radius of the 3D exciton. The perturbation approximation may become adequate in the case of small lateral size. According to the available data in the literature, the radius of the 3D exciton in CdSe is approximately 5–6 nm [Let us now turn to the possibility of considering the electrostatic interaction between an electron and a hole during interband transitions when conditions Equation (7) are satisfied in the CdSe and PbS samples in the framework of perturbation theory. The following fact can justify the usage of perturbation theory in this size quantization regime. The typical sizes of NPLs in the y 5–6 nm ,57,58.On the other hand, the thickness of the CdSe NPLs is 1–2.5 nm , and the3968 meV ,55,59 wi3968 meV ,61,62. IHere Accounting for the exciton effects in the case of strong quantization leads to a decrease in the threshold frequency from Equation (11) by the following frequency shift:e–h electrostatic interaction in the case of PbS is several times smaller than in the case of CdSe. This is due to the weaker electron–hole coupling in PbS than in CdSe. It can be seen from e–h interaction from expression Equation (15) occurs.As can be seen from the In the mode of moderate quantization, it is assumed that the following conditions are satisfied for the geometric dimensions of the NPL ,50,51:ΨNThe total energy minimization condition with respect to the variational parameter has the following form:The following calculations for the ng forms ,36,62,63Substituting Equations (19), (20) and (22) into Equation (21) and performing numerical calculations of the integral from (19), we obtain the values of the parameter In the case of intermediate quantization, for the threshold energy of the interband transitions, we have:Substituting the values of the parameter e sample b,c. e–h interaction weakens with the increase of the charge carrier’s localization area. otential b and theotential c. The poLet us now consider the interband absorption coefficient in the NPL in the case of moderate quantization of the carrier motion. For the matrix element of the interband transitions, in this case, we can consider :(24)Mc,vSubstituting now Equations (18), (19), (20) into Equation (24) for the matrix element of the interband transitions, we obtain:For the absorption coefficient during transitions to the ground exciton state, we obtain, in this case:XY plane. The frequency dependence of the absorption has a resonant character, and the position of the peaks is determined by the threshold energy value As can be seen, the intensity of the interband absorption, in this case, is determined by the geometric dimensions of the sample in the In weak quantization mode, it is assumed that the following conditions are satisfied for the geometric dimensions of the NPL ,54,55:(2When conditions Equation (25) are satisfied, the electrostatic interaction between an electron and a hole, as is known, occurs mainly in the NPL plane ,61,62,63To obtain the wave function and corresponding energy in the growth direction in the model of finite well potential, the Schrödinger equation with such potential also considered the self-potential that occurs due to dielectric constants mismatch is solved numerically. In the regime of weak size quantization, the motion of an electron–hole pair in the NPL plane is separated from the motion of the center of inertia of the bound electron–hole pair and the relative motion of the quasi-two-dimensional hydrogen-like electron–hole formation itself. The exciton states can be considered separately ,61,64. TThe relative motion is symmetric in the NLP plane; thus, it is possible to further separate the relative motion and consider only the radial part. The radial part of wave functions of the relative motion of the electron and hole can be obtained by numerically solving the Schrodinger equation: Here ε = 6–10, strictly speaking, do not allow one to use condition Equation (33) with sufficient accuracy and to calculate the exciton binding energy in NPL in the potential approximation that will be adequate to condition Equation (31). Our calculations unambiguously show that, in the case of CdSe, the choice of the electron–hole interaction potential in the form Z-axis, and secondly, the less significant difference between 1S state, obtained the result When condition Equation (32) passes into the condition:otential ,48,63,65dSe NPLs ,64. Obtaented in , where wthors in  for the 1S state for different NPL thicknesses is shown in Z-direction, which leads to stronger electron–hole effective potential and, thus smaller effective localization areas. This also can be seen in The comparison of calculations at given in . The exc1S state with different NPL thicknesses for CdSe and PbS, respectively. The numerically calculated exciton wave function can be approximated by the 1S exciton wave function with an estimated exciton Bohr radius For the matrix element of the interband transition in the case of weak quantization, we can consider : (35)|McThe following expression gives the threshold frequency of the interband transitions to the final exciton state:Consideration of exciton states in PbS NPL has several features. The binding energy of exciton is sensitive to material parameters. In addition, it is necessary to consider the dependence of the values of the effective mass and other optical characteristics of the sample on the thickness . At the y (ε=17) . The they (ε=17) ,49 see ay (ε=17) . For exay (ε=17) . In our binding energy calculations considering the dielectric constant mismatch in material and environment and using the Takagahara ,69 formuvided in . A smallThe results obtained in this work, along with the discussion and comparison with the results of other works, show that the analytical and numerical calculation methods used in the work for each specific size quantization regime allow us to provide an adequate quantitative description of the characteristics of the optical absorption in CdSe and PbS nanoplates. The obtained values of threshold frequencies and exciton binding energies agreed with the experimental data. It has been demonstrated that in the NPLs under consideration, the effective mass and dielectric coefficient strongly depend on the number of sample monolayers and therefore impact the description of single-particle and excitonic states. The suggested approach and corresponding calculations show that in CdSe and PbS NPLs, the naïve usage of the two-dimensional Coulomb potential leads to inaccurate physical results. Therefore, taking into account the essential difference between the dielectric constant of the NPL and surrounding material provides much more adequate results of exciton description in NPLs. In both cases, the exciton binding energy significantly exceeds the values computed in the two-dimensional Colomb interaction model framework. It has been shown that the physical principles and calculation methods used in work can also be used when considering optical transitions in nanoplatelets of other materials of compounds II–VI and IV–VI. In addition, the results can be further used to describe the statistical properties of charge carriers when considering the collective properties of low-dimensional excitons in nanoplatelets.