Homogeneous Sample Research Articles

Rare earth samarium substituted barium-calcium hexaferrites: Insight into structure, dielectric and magnetic aspects

This study presents the synthesis of samarium-substituted Ba-Ca hexaferrites (Ba0.5Ca0.5Fe12-xSmxO19) utilizing the sol–gel method. X-ray diffraction (XRD) analysis is performed to evaluate the structure of fabricated materials. The lattice shows an expansion up to a doping concentration of x = 0.12, and minor contraction at x = 0.16. Both X-ray density and bulk density exhibit an upward trend with increasing doping levels, while porosity reduces and dislocation density shows an increase. Scanning electron microscopy (SEM) confirms the homogeneity and uniformity of the doped samples. The dielectric properties displays the interaction of the materials with an external electric field, revealing that the dielectric constant (ε′), dielectric loss (ε″), and dissipation factor progressively increases with samarium concentration. Magnetic characterizations demonstrate a significant enhancement in saturation magnetization and coercivity, attaining peak values of 33.19 emu/g and 1.805 kOe, respectively. Moreover, the anisotropy field (Ha) and anisotropy constant (K) shows an increase with higher doping concentrations confirming the prepared material as an alternative for electric and magnetic industry applications.

Magnetostructural transformation and magnetocaloric response in Mn(Fe)NiSi(Al) alloys

An efficient magnetocaloric refrigerant must have certain characteristics such as a sharp transition near the desired working temperature, a large cyclic magnetocaloric response, and the use of raw materials with reduced costs and low environmental consequences. In this sense, this work focuses on a series of rare-earth- and Co-free Mn0.5Fe0.5NiSi1-xAlx alloys (x = 0.0525, 0.060, 0.0685) with promising magnetocaloric properties. The alloys were synthesized using combined arc melting and induction melting techniques, as this synthesis route provides improved control on the sample composition and homogeneity. We investigated how the heat treatment temperature and Al content affect the magnetostructural and magnetocaloric properties of the alloys. On the one hand, it is found that annealing at 1173 K for 7 days leads to a sharp magnetostructural transformation with no traces of impurities for the alloy with x = 0.0525. Under these conditions, a large isothermal entropy change of –11.5 J kg−1 K−1 for 1 T is obtained near room temperature, significantly improving the value of the as-cast sample. On the other hand, following this optimal heat treatment, the influence of Al content is studied: upon increasing the Al concentration the magnetostructural transformation shifts to lower temperatures, ranging from 320 K for x = 0.0525 to 220 K for x = 0.0685 (measured upon heating).

B-learning in human anatomy: Comparative analysis of academic achievement between face-to-face and e-learning modalities

IntroductionIn recent years, modern technologies have become established in most educational fields. Thus, e-learning tends to be an integral part of the learner-centered learning process, with the teacher acting as a facilitator. However, the methodologies used to study the impact of e-learning have been varied and imprecise, making comparison and meta-analysis difficult. This study attempts to overcome these obstacles with a large and homogeneous sample to compare (1) the academic outcomes obtained with face-to-face and e-learning in a blended module of human anatomy and (2) the response attempts (response index) of each student in answering questions specific to each learning modality. Material and methodsThe results of the multiple-choice exams under study were collected. All students (n=1160) were from four consecutive academic years following the same teaching program with a b-learning method: 13 topics were presented face to face by the same lecturers, and six via e-learning with the same online resources. Two variables were compared: (1) the academic grade, based on the score for correct answers and the penalty for incorrect ones, and (2) the response index, based on the number of correct and incorrect answers. Results(1) 73.45 % of the examinees passed the test. In the sample as a whole, results were better in face-to-face than in e-learning. In the quartiles ordered by overall academic performance, this superiority was limited to the top half of the higher-performing students. In contrast, lower-scoring students performed better in e-learning. However, these differences were modest (≤ 0.54 points). (2) In proportion, the questions on topics learned face-to-face were the most frequently answered. A strong correlation was observed between the variables in the whole sample and the students with the highest academic scores (first quartile) on the global exam and the questions on topics learned in each modality. In the remaining quartiles, the correlation was also strong in the e-learning content. Conclusions(1) Both modalities included in b-learning are academically effective. (2) Proportionally, students take more risks when answering content questions learned in face-to-face classes, and there is a strong correlation between response attempts and academic grades, especially, on the brightest exams and e-learning content.

Measurement of attachment in human-animal interaction research

Abstract Researchers in the field of human-animal interaction often investigate the construct of the human-animal bond in order to measure contextual information about companion-animal relationships beyond simply living with a pet. This practice allows researchers to go beyond a simple manifest variable (e.g., dog-owning vs. cat-owning participants) to investigate how specific relationships with companion animals may impact outcomes. However, the current measures of the relationship between people and their pets (i.e., attachment) are flawed. Specifically, their initial validations were based on homogenous samples, the original conceptualizations of the human-animal bond were fragmented, and some used improper statistical techniques in determining the underlying factor structure of the measure. The current study utilized confirmatory factor analysis ( n = 589) to examine the factor structure and underlying psychometric properties of the Lexington Attachment to Pets Scale and the Short Attachment to Pets Scale. The factor analysis revealed that the Lexington Attachment to Pets Scale and the Short Attachment to Pets Scale both have issues with model fit in a sample of undergraduate students at a public Southwestern University. This article offers recommendations for future research investigating the human-animal bond.

Energy-dispersive Laue diffraction analysis of the influence of statherin and histatin on the crystallographic texture during human dental enamel demineralization.

Energy-dispersive Laue diffraction (EDLD) is a powerful method to obtain position-resolved texture information in inhomogeneous biological samples without the need for sample rotation. This study employs EDLD texture scanning to investigate the impact of two salivary peptides, statherin (STN) and histatin-1 (HTN) 21 N-terminal peptides (STN21 and HTN21), on the crystallographic structure of dental enamel. These proteins are known to play crucial roles in dental caries progression. Three healthy incisors were randomly assigned to three groups: artificially demineralized, demineralized after HTN21 peptide pre-treatment and demineralized after STN21 peptide pre-treatment. To understand the micro-scale structure of the enamel, each specimen was scanned from the enamel surface to a depth of 250 µm using microbeam EDLD. Via the use of a white beam and a pixelated detector, where each pixel functions as a spectrometer, pole figures were obtained in a single exposure at each measurement point. The results revealed distinct orientations of hydroxyapatite crystallites and notable texture variation in the peptide-treated demineralized samples compared with the demineralized control. Specifically, the peptide-treated demineralized samples exhibited up to three orientation populations, in contrast to the demineralized control which displayed only a single orientation population. The texture index of the demineralized control (2.00 ± 0.21) was found to be lower than that of either the STN21 (2.32 ± 0.20) or the HTN21 (2.90 ± 0.46) treated samples. Hence, texture scanning with EDLD gives new insights into dental enamel crystallite orientation and links the present understanding of enamel demineralization to the underlying crystalline texture. For the first time, the feasibility of EDLD texture measurements for quantitative texture evaluation in demineralized dental enamel samples is demonstrated.

Mothers of Children with Stuttering and Their Daily Concerns: A Qualitative Study

Background: Stuttering is one of the most important speech disorders in children, which causes anxiety and worry in parents, especially mothers. The present study sought to investigate and identify the types of anxiety experienced by mothers of children with stuttering. Methods: This qualitative study adopted reflexive thematic analysis (Brown & Clark) to investigate the anxiety and concerns experienced by mothers of children with stuttering. The participants were 15 mothers of children with stuttering who visited speech therapy centers in Isfahan and were selected through homogenous purposive sampling. The data were collected through interviews with the participants for 45 days and analyzed by the thematic analysis method. Results: Data analysis revealed two core categories, four organizing themes, and nineteen subthemes. The two core categories identified in this study were mother-centered anxiety (anxiety about public judgments on the mother and anxiety about the appropriateness of the mother’s behavior with the child who stutters) and child-centered anxiety (concerns about public reactions to the child’s stuttering and the concerns about the child’s future life and treatment). Conclusion: The findings indicated that the mothers of children with stuttering were mostly concerned about public reactions to the stuttering child and their judgments about the mother. Thus, promoting a sense of self-worth in these mothers can reduce such concerns. Moreover, raising public awareness about how to treat children with stuttering and their parents can make social life easier for such children and their mothers.

Implikasi Laba Operasi dan Modal Kerja terhadap Laba Bersih PT. Nippon Indosari Corpindo

In the background of this research problem, namely, operating costs have increased and working capital has decreased while net profit has increased, which should make high operating costs lower profits and lower working capital lower net profit. The occurrence of this phenomenon so researchers raised this issue.This study uses quantitative research methods and sampling using purposive sampling techniques with homogeneous sampling category criteria. The results of the research found from the three variables used that have an influence, namely operating profit has a significant effect on net profit with a value of 0.0000 and after being tested simultaneously operating profit also has a significant effect on net profit with a value of 0.0000 while working capital has no effect on net profit with a value of 0.1483. From the results of the study, the authors draw a conclusion that working capital does not always decrease will make net profit decrease. excess income is based on low operating profit and high working capital.

Examining the Benefits of an Educational Blog for Supporting Student Mental Health: A Quasi-Experimental Study

This quasi-experimental study examined the use of a blog as a mental health resource for students. The main objective was to determine if occupational therapy graduate students benefited from using a resource to support their mental health. A purpose-specific survey was used to assess student perceptions. Sixty-five students participated in the survey and 73% of those students reported the blog helped them to manage their mental health. The results indicate that using a blog as a strategy to support student mental health is beneficial. This study is limited by a small homogenous sample; however, serves as a resource for educators.

Effect of modification of nonwoven textiles with biochar and multi-walled carbon nanotubes on their dielectric properties

Dielectric properties of native nonwoven textile as well as textile with bound biochar and multi-walled carbon nanotubes in the frequency range of 10 to 5·105 Hz and at the temperatures of 30 to 60 °C have been investigated. The capacity of native nonwoven textile has been shown to decrease with the temperature according to the Arrhenius law. The activation energy of the temperature dependence of the capacity has been estimated to be 0.09 eV. It has been demonstrated that regardless of the temperature, the frequency dependence of the resistance of the nonwoven textile can be described by two exponential functions. In the presence of bound biochar and multi-walled carbon nanotubes in the nonwoven textile, the conductivity current was 4 orders of magnitude greater than the bias current and increased with the temperature according to the Arrhenius law. The activation energy of the temperature dependence of the inverse resistance (an analogue of the conductivity for homogeneous samples with the same dimensions) has been estimated to be 0.19 eV for the samples with multi-walled carbon nanotubes and 0.62 eV for the samples with bound biochar.

The effects of internship abroad on engineering students’ self-perceived employability

ABSTRACT Internationalisation is seen as one of the means of enabling engineering students to acquire skills and attitudes and also promote their employability. In this study, we investigate the effects of a six-month internship abroad on self-perceived employability, by (1) observing the global effect of the internship abroad on factors related to self-perceived employability (SPE), (2) analysing the effects depending on demographic and organisation questions, (3) Verifying through clustering if the data can identify homogeneous groups of students based on SPE change and (4) predicting SPE positive change relating to the internship abroad. We conducted a quantitative study on SPE before and after the internship abroad, analysed sample homogeneity (clustering) and assessed the internship's role in SPE change using logistic regression. The results show that (1) Some factors have a high/low level of influence on SPE; (2) demographic and organisational factors do not affect SPE change; (3) two homogenous groups appeared in terms of SPE change (a positive group and a negative group); (4) only social integration support predicts positive change in SPE for engineering students. The SPE of engineering students seems to be linked to a wider range of perceived social support in their host country.

The Optimization of the Osborne Extraction Method for the Fractionation and Characterization of Oat Proteins

The growing number of wheat-related allergies worldwide has resulted in a new trend towards gluten-free alternatives. In this context, alternative cereals such as sorghum and oats are attracting new interest. Given the limited data available, the question of whether these cereals are completely safe and gluten-free for allergy sufferers remains open. One of the key steps in protein research is their efficient extraction. In this work, the Osborne sequential extraction method was developed and optimized using the response surface methodology in order to fractionate oat proteins. An optimized desirability of 0.986 was achieved with an extraction time of 4.7 min, a speed of 6, and a sample/solvent ratio of 5. The corresponding optimized responses were 8.7, 4.0, and 5.1% for the extraction yields of the avenin, avenalin, and albumin/globulin fractions, respectively. Further characterization of the extracts was carried out on 24 homogeneous and commercial oat samples via LC-MS/MS, targeting six potentially allergenic proteins. The avenin-E protein featured prominently, with relative contents of 60.7, 32.2, 58.0, and 59.8% in the total extract, avenin, avenalin, and albumin/globulin fractions, respectively, while the Avenin-3, ATI-2, avenin, SSG2, and SSG1 proteins in the total extract showed levels of 16.4, 9.3, 6.6, 4.8, and 2.2%, respectively. The preliminary results of an ELISA performed on the different fractions revealed low levels of gluten (from 1.24 ± 0.14 to 3.61 ± 0.16 mg/kg), which were well below the threshold limit of 20 mg/kg. These results support the hypothesis that oats can be a safe food for people suffering from cereal-related allergies. These results open the door to further studies into the comprehensive characterization of oat proteins.

Comment on, "Increased expression of ephrin A1 in brain arteriovenous malformation: DNA microarray analysis".

This study by Sasahara et al. explores the role of ephrin A1 in brain arteriovenous malformations (AVM) using DNA microarray analysis, quantitative real-time RT-PCR, and immunohistochemistry. The research identifies significant upregulation of ephrin A1 in AVM, suggesting its potential involvement in the abnormal vascular architecture characteristic of this condition. The study's innovative methodology and thorough exploration of gene expression patterns contribute valuable insights into AVM pathogenesis, highlighting ephrin A1 as a potential therapeutic target. However, the study's limitations include clinical variability among patient samples and the use of draining veins as controls, which may affect the robustness of the findings. Future research should address these limitations by using more homogeneous samples and expanding the investigation to include other ephrin family members. This could provide a broader understanding of ephrin signaling in AVM and guide the development of targeted therapies.

Structural Heterogeneity of the Rabies Virus Virion.

Rabies virus (RABV) is among the first recognized viruses of public health concern and has historically contributed to the development of viral vaccines. Despite these significances, the three-dimensional structure of the RABV virion remains unknown due to the challenges in isolating structurally homogenous virion samples in sufficient quantities needed for structural investigation. Here, by combining the capabilities of cryogenic electron tomography (cryoET) and microscopy (cryoEM), we determined the three-dimensional structure of the wild-type RABV virion. Tomograms of RABV virions reveal a high level of structural heterogeneity among the bullet-shaped virion particles encompassing the glycoprotein (G) trimer-decorated envelope and the nucleocapsid composed of RNA, nucleoprotein (N), and matrix protein (M). The structure of the trunk region of the virion was determined by cryoEM helical reconstruction, revealing a one-start N-RNA helix bound by a single layer of M proteins at an N:M ratio of 1. The N-M interaction differs from that in fellow rhabdovirus vesicular stomatitis virus (VSV), which features two layers of M stabilizing the N-RNA helix at an M:N ratio of 2. These differences in both M-N stoichiometry and binding allow RABV to flex its N-RNA helix more freely and point to different mechanisms of viral assembly between these two bullet-shaped rhabdoviruses.

Strategic Dominance and Its Role in Reducing Consumer Arrogance (An Analytical Study of the Opinions of a Sample of Workers in Electronic Product Sales Centers in Najaf Governorate)

The current study explores the relationship between two main variables: strategic dominance in its dimensions (strategic rules, organizational power, strategic maneuvering, strategic sovereignty) and consumer arrogance in its dimensions (image-based consumption, consumer bragging, incentive-based purchases, consumer sense of superiority), through a survey of the opinions of a sample of workers in electronic product sales centers in Najaf Governorate. The researcher used the homogeneous intentional sample method. To achieve this goal, the questionnaire was used as a main tool to collect the required data. The questionnaire was distributed to (180) workers from the community under study. After reviewing it, the number of questionnaires valid for statistical analysis reached (172) questionnaires, out of the number of retrieved questionnaires, which amounted to (176) questionnaires. It was statistically analyzed using the programs (SPSS.28) and (AMOS.V.26), and the results showed the presence of a significant effect and correlation between strategic dominance in reducing consumer arrogance. The results reached by the current study are an attempt to reduce or bridge the knowledge gap between the study variables of strategic dominance and consumer arrogance. The study recommends that the administrations of electronic product sales centers in Najaf under study should adopt the components of strategic dominance and the new ideas it includes in the research and development department and encourage them, and enable workers to provide new ideas and involve them in the decision-making process, which contributes to reducing consumer arrogance. It also calls on researchers to conduct more future studies and research within the scope of the current study variables in the Iraqi organizational environment or environments in other countries.

A Comparative Study Of The Meaning Of Life, Academic Motivation, Learning Styles, Study Habits, And Academic Achievement Between University And College Students In Different Educational Institutions

In the rapidly evolving landscape of education, understanding the factors that contribute to students' academic success is more critical than ever. This study aimed to conduct a comparative analysis of the meaning of life, academic motivation, learning styles, study habits, and academic achievement between university and college students across different educational institutions. Using a sample of 800 participants, equally divided between university and college students, data were collected through validated questionnaires, including the Purpose in Life Test, Academic Motivation Scale, VARK Learning Styles Questionnaire, and Study Habits Inventory. Academic achievement was assessed using students' GPA records and their most recent semester results. Descriptive statistics, independent samples t-tests, and correlation analyses were employed to analyze the data. The results indicated that university students exhibited significantly higher levels of meaning of life, academic motivation, and study habits compared to college students. Positive correlations were identified between meaning of life and academic motivation, as well as between study habits and academic achievement, suggesting that these variables are interlinked in influencing student performance. Furthermore, regression analysis demonstrated that academic motivation, learning styles, and study habits significantly predicted the meaning of life in students, accounting for 62% of the variance. The study's findings underscore the importance of fostering educational practices that enhance intrinsic motivation, promote a sense of purpose, and support effective study strategies in students. These insights are crucial for educators, policymakers, and institutions aiming to create learning environments that facilitate both academic success and personal development. Limitations of the study include its reliance on self-reported data and the relatively homogenous sample, suggesting that future research should focus on more diverse populations and longitudinal approaches to understand the long-term effects of these educational factors on student outcomes.

Optimising 4D imaging of fast-oscillating structures using X-ray microtomography with retrospective gating

Imaging the internal architecture of fast-vibrating structures at micrometer scale and kilohertz frequencies poses great challenges for numerous applications, including the study of biological oscillators, mechanical testing of materials, and process engineering. Over the past decade, X-ray microtomography with retrospective gating has shown very promising advances in meeting these challenges. However, breakthroughs are still expected in acquisition and reconstruction procedures to keep improving the spatiotemporal resolution, and study the mechanics of fast-vibrating multiscale structures. Thereby, this works aims to improve this imaging technique by minimising streaking and motion blur artefacts through the optimisation of experimental parameters. For that purpose, we have coupled a numerical approach relying on tomography simulation with vibrating particles with known and ideal 3D geometry (micro-spheres or fibres) with experimental campaigns. These were carried out on soft composites, imaged in synchrotron X-ray beamlines while oscillating up to 400 Hz, thanks to a custom-developed vibromechanical device. This approach yields homogeneous angular sampling of projections and gives reliable predictions of image quality degradation due to motion blur. By overcoming several technical and scientific barriers limiting the feasibility and reproducibility of such investigations, we provide guidelines to enhance gated-CT 4D imaging for the analysis of heterogeneous, high-frequency oscillating materials.

The fundamental plane of black hole activity for low-luminosity radio active galactic nuclei across 0 < z < 4

Context. The fundamental plane of black hole activity describes the correlation between radio luminosity (LR), X-ray luminosity (LX), and black hole mass (MBH). It reflects a connection between the accretion disc and the jet. However, the dependence of the fundamental plane on various physical properties of active galactic nuclei (AGNs) and host galaxies remains unclear, especially for low-luminosity AGNs, which is important for understanding the accretion physics in AGNs. Aims. Here, we explore the dependence of the fundamental plane on the radio loudness, Eddington-ratio (λEdd), redshift, and galaxy star formation properties (star-forming galaxies and quiescent galaxies) across 0.1 < z ≤ 4 for radio AGNs. Based on current deep and large surveys, our studies can extend to lower luminosities and higher redshifts. Methods. From the deep and large multi-wavelength surveys in the GOODS-N, GOODS-S, and COSMOS/UltraVISTA fields, we constructed a large and homogeneous radio AGN sample consisting of 208 objects with available estimates for LR and LX. Then we divided the radio AGN sample into 141 radio-quiet AGNs and 67 radio-loud AGNs according to the radio loudness defined by the ratio of LR to LX, and explored the dependence of the fundamental plane on different physical properties of the two populations, separately. Results. The ratio of LR to LX shows a bimodal distribution that is well described by two single Gaussian models. The cross point between these two Gaussian components corresponds to a radio-loudness threshold of log(LR/LX) = − 2.73. The radio-quiet AGNs have a significantly larger Eddington ratio than the radio-loud AGNs. Our radio-quiet and radio-loud AGNs show a significantly different fundamental plane, which indicates a significant dependence of the fundamental plane on the radio loudness. For both radio-quiet and radio-loud AGNs, the fundamental plane shows a significant dependence on λEdd, but no dependence on redshift. The fundamental plane shows a significant dependence on the galaxy star formation properties for radio-quiet AGNs, while for radio-loud AGNs this dependence disappears. Conclusions. The fundamental plane sheds important light on the accretion physics and X-ray emission origins of central engines. X-ray emission of radio-quiet AGNs at 0.01 < λEdd < 0.1 are produced by a combination of advection-dominated accretion flow (ADAF) and synchrotron radiation from the jet, while at 0.1 < λEdd < 1 they mainly follow the synchrotron jet model. The origins of X-ray emission of radio-loud AGNs are consistent with a combination of ADAF and the synchrotron jet model at λEdd < 0.01, agree with the synchrotron jet model at 0.01 < λEdd < 0.1, and follow a combination of the standard thin disc and a jet model at λEdd > 0.1.

Crowdsourced data as a strategic approach to include the human dimension in outdoor environmental quality assessments

Outdoor environments extend living spaces as venues for various activities. Comfortable open public spaces can positively impact citizens' health and well-being, thereby improving the livability and resilience of cities. Considering the visitors' perception of these environments in comfort studies is crucial for ensuring their well-being and promoting the use of these spaces. However, traditional survey methods may be time- and resource-consuming to gather significant sample sizes, usually focusing on selected homogeneous samples. Crowdsourced data, then, has emerged as an alternative for assessing human perception, as it eases the collection of subjective feedback and potentially amplifies impact and inclusivity. This study presents a strategic approach for analyzing publicly available and willingly reported crowdsourced data from a digital mapping platform in outdoor comfort evaluations, aiming to verify whether these data are informative regarding environmental quality perception and to identify the environmental factors that people are most sensitive to. Urban parks located in New York City served as a case study. A multi-source, interdisciplinary information framework combined crowdsourced reviews with environmental data used to determine prevailing thermal conditions. Overall perception of parks was well-rated, revealing that their attractions and activities are probably the most appealing characteristics for park attendance. Regarding environmental perception, acoustic and thermal factors are clearly the most influential. Acoustics were well-rated, while the main aspect regarding the thermal domain is the recognition of shading as a mitigator for hot conditions. Environmental data provided complementary insights, particularly concerning the range of thermal sensations experienced in urban parks. The findings confirm that willingly reported crowdsourced data can provide valuable insights into urban crowd environmental perception, presenting a potentially suitable and effective method to include the human perspective in environmental quality assessments, as well as to evaluate and predict environmental-related risks.

Discrepancy-based diffusion models for lesion detection in brain MRI

Diffusion probabilistic models (DPMs) have exhibited significant effectiveness in computer vision tasks, particularly in image generation. However, their notable performance heavily relies on labelled datasets, which limits their application in medical images due to the associated high-cost annotations. Current DPM-related methods for lesion detection in medical imaging, which can be categorized into two distinct approaches, primarily rely on image-level annotations. The first approach, based on anomaly detection, involves learning reference healthy brain representations and identifying anomalies based on the difference in inference results. In contrast, the second approach, resembling a segmentation task, employs only the original brain multi-modalities as prior information for generating pixel-level annotations. In this paper, our proposed model – discrepancy distribution medical diffusion (DDMD) – for lesion detection in brain MRI introduces a novel framework by incorporating distinctive discrepancy features, deviating from the conventional direct reliance on image-level annotations or the original brain modalities. In our method, the inconsistency in image-level annotations is translated into distribution discrepancies among heterogeneous samples while preserving information within homogeneous samples. This property retains pixel-wise uncertainty and facilitates an implicit ensemble of segmentation, ultimately enhancing the overall detection performance. Thorough experiments conducted on the BRATS2020 benchmark dataset containing multimodal MRI scans for brain tumour detection demonstrate the great performance of our approach in comparison to state-of-the-art methods.

An ultrasensitive and specific fluorescence split-aptasensor for VEGF165 detection based on nicking enzyme-assisted 3D DNA walker coupling with CRISPR-Cas12a

The overexpression of vascular endothelial growth factor 165 (VEGF165) in cancer cells plays a pivotal role in promoting tumor metastasis by facilitating their excessively rapid proliferation and division. Hence, the development of analytical methods possessing high sensitivity and resistance to interference is imperative for the detection of VEGF165. Various types of aptasensors have been devised for VEGF165 detection; however, the performance of these biosensors can be influenced by non-target signals caused by conformational changes in unbound aptamers. The paper shows the creation of a precise and sensitive fluorescence biosensor designed to detect VEGF165 by using a VEGF165-specific split aptamer. Additionally, this biosensor employs nicking enzyme-assisted DNA walker coupling with CRISPR-Cas12a to achieve dual-signal amplification. The VEGF165 calibration curve shows a detection limit of 268 fM and has a broad linear range from 5 to 4000 nM. The fluorometric biosensor was utilized to detect VEGF165 in human serum and cellular homogenate samples, yielding good outcomes. The innovative design serves as proof of concept and demonstrates significant potential in detecting various targets.