A Preliminary Investigation of the Technology Acceptance Model (TAM) in Early Childhood Education and Care

The technology acceptance model (TAM) is a well-known postmodern idea that explains how humans adopt and use new technologies. The model focuses on variables that impact behavioral intention to use new technology from the perspective of the end user. The purpose of this study was to construct a viable questionnaire for assessing preschool teachers' technology acceptability in online instruction in ECEC, based on data collected from 182 Romanian preschool instructors, using the theory of planned behavior framework. Our application of theory of planned behavior in technology adoption in ECEC is extraordinarily good, with 66 percent explained variance of actual usage of technology in class. The research literature supports the findings that the intention to use technology and a good attitude toward technology are the most significant determinants of actual technology usage. Although more research is needed in larger and more complex samples to confirm these findings, there is compelling evidence that the prediction methodology can be used to predict preschool teachers' level of technology acceptance and assist educational decision-makers in designing timely interventions that improve the chances of success. The study's major findings point to crucial variables that might help national educational decision-makers improve technology adoption in ECEC.</em

CYTOGENETIC EFFECTS INDUCED BY PHENOLIC COMPOUNDS IN LYCOPERSICON ESCULENTUM MILL

The aim of this paper is to evaluate the effects of the phenolic compounds extracted from spruce bark on cells from the radicular apex of Lycopersicon esculentum Mill. We found that different concentrations of polyphenols and the time of treatment modified the frequency of cells division and the number of mitotic ana-telophases with aberrations

New Insights into the Biological Response Triggered by Dextran-Coated Maghemite Nanoparticles in Pancreatic Cancer Cells and Their Potential for Theranostic Applications

Iron oxide nanoparticles are one of the most promising tools for theranostic applications of pancreatic cancer due to their unique physicochemical and magnetic properties making them suitable for both diagnosis and therapy. Thus, our study aimed to characterize the properties of dextran-coated iron oxide nanoparticles (DIO-NPs) of maghemite (γ-Fe2O3) type synthesized by co-precipitation and to investigate their effects (low-dose versus high-dose) on pancreatic cancer cells focusing on NP cellular uptake, MR contrast, and toxicological profile. This paper also addressed the modulation of heat shock proteins (HSPs) and p53 protein expression as well as the potential of DIO-NPs for theranostic purposes. DIO-NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering analyses (DLS), and zeta potential. Pancreatic cancer cells (PANC-1 cell line) were exposed to different doses of dextran-coated ɣ-Fe2O3 NPs (14, 28, 42, 56 μg/mL) for up to 72 h. The results revealed that DIO-NPs with a hydrodynamic diameter of 16.3 nm produce a significant negative contrast using a 7 T MRI scanner correlated with dose-dependent cellular iron uptake and toxicity levels. We showed that DIO-NPs are biocompatible up to a concentration of 28 μg/mL (low-dose), while exposure to a concentration of 56 μg/mL (high-dose) caused a reduction in PANC-1 cell viability to 50% after 72 h by inducing reactive oxygen species (ROS) production, reduced glutathione (GSH) depletion, lipid peroxidation, enhancement of caspase-1 activity, and LDH release. An alteration in Hsp70 and Hsp90 protein expression was also observed. At low doses, these findings provide evidence that DIO-NPs could act as safe platforms in drug delivery, as well as antitumoral and imaging agents for theranostic uses in pancreatic cancer

Exposure to Iron Oxide Nanoparticles Coated with Phospholipid-Based Polymeric Micelles Induces Renal Transitory Biochemical and Histopathological Changes in Mice

The renal toxicity induced by the intravenously injected iron oxide nanoparticles (IONPs) encapsulated in phospholipid-based polymeric micelles was studied in CD1 mice for 2 weeks. Two doses of 5 and 15 mg of Fe/kg bodyweight of NPs or saline solution (control) were tested, and the levels of antioxidant enzyme activities, oxidative stress parameters, and the expressions of kidney fibrosis biomarkers were analyzed. The enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, glutathione reductase, and glucose-6-phosphate dehydrogenase in the kidney were significantly decreased compared to the control in the first 3 days followed by a recovery up to 14 days. Concomitantly, a significant increase in lipid peroxidation (malondialdehyde) levels and a decrease in protein thiol groups were recorded. Moreover, increases in the expressions of T cell immunoglobulin and mucin domain 1 (TIM-1) and transforming growth factor-β (TGF-β) were observed in mouse tissue samples in the first week, which were more pronounced for the higher dose. The results suggested the role of oxidative stress as a mechanism for induced toxicity in mice kidneys after the IV administration of IONPs encapsulated in phospholipid-based polymeric micelles but also the capacity of the kidneys’ defense systems to revert efficiently the biochemical modifications that were moderate and for short duration

Coating Dependent In Vitro Biocompatibility of New Fe-Si Nanoparticles

Magnetic nanoparticles offer multiple utilization possibilities in biomedicine. In this context, the interaction with cellular structures and their biological effects need to be understood and controlled for clinical safety. New magnetic nanoparticles containing metallic/carbidic iron and elemental silicon phases were synthesized by laser pyrolysis using Fe(CO)5 vapors and SiH4 gas as Fe and Si precursors, then passivated and coated with biocompatible agents, such as l-3,4-dihydroxyphenylalanine (l-DOPA) and sodium carboxymethyl cellulose (CMC-Na). The resulting magnetic nanoparticles were characterized by XRD, EDS, and TEM techniques. To evaluate their biocompatibility, doses ranging from 0&ndash;200 &micro;g/mL hybrid Fe-Si nanoparticles were exposed to Caco2 cells for 24 and 72 h. Doses below 50 &mu;g/mL of both l-DOPA and CMC-Na-coated Fe-Si nanoparticles induced no significant changes of cellular viability or membrane integrity. The cellular internalization of nanoparticles was dependent on their dispersion in culture medium and caused some changes of F-actin filaments organization after 72 h. However, reactive oxygen species were generated after exposure to 25 and 50 &mu;g/mL of both Fe-Si nanoparticles types, inducing the increase of intracellular glutathione level and activation of transcription factor Nrf2. At nanoparticles doses below 50 &mu;g/mL, Caco2 cells were able to counteract the oxidative stress by activating the cellular protection mechanisms. We concluded that in vitro biological responses to coated hybrid Fe-Si nanoparticles depended on particle synthesis conditions, surface coating, doses and incubation time

Response of the Endogenous Antioxidant Defense System Induced in RAW 264.7 Macrophages upon Exposure to Dextran-Coated Iron Oxide Nanoparticles

Presently, iron oxide nanoparticles are the only ones approved for clinical use as contrast agents in magnetic resonance imaging (MRI). Even though there is a high demand for these types of nanoparticles both for clinical use as well as for research, there are difficulties in obtaining stable nanoparticles with reproducible properties. In this context, in this study, we report the obtaining by an adapted coprecipitation method of dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs). The morphology and structure of the dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM and SEM micrographs highlighted the obtaining of particles of nanometric size and spherical shape morphology. Furthermore, the high-resolution transmission electron microscopy (HRTEM), as well as selected area diffraction (SAED), revealed that the obtained samples presented the structure of cubic maghemite. In this study, we also explored the effects of the co-precipitation synthesized dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) on the redox status of macrophages. For cytotoxicity evaluation of these NPs, murine macrophages (RAW 264.7 cell line) were exposed to different concentrations of dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) corresponding to 0–500 μg Fe3+/mL and incubated for 24, 48, and 72 h. Intracellular iron uptake, changes in the oxidative stress parameters (reactive oxygen species production and malondialdehyde level), and the activity of antioxidant enzymes, as well as GSH concentration in cells, were evaluated after incubation with a lower (50 μg Fe3+/mL) and higher (500 μg Fe3+/mL) dose of NPs. The results indicated a significant decrease in RAW 264.7 cell viability after 72 h in the presence of NPs at concentrations above 25 μg Fe3+/mL. An important accumulation of NPs, dependent on dose and exposure time, was detected in macrophages, but it induced only a limited raise in the oxidative status. We showed here that the antioxidant capacity of RAW 264.7 macrophages was efficient in counteracting dextran-coated maghemite nanoparticles (ɤ-Fe2O3 NPs) toxicity even at higher doses

Response of the Endogenous Antioxidant Defense System Induced in RAW 264.7 Macrophages upon Exposure to Dextran-Coated Iron Oxide Nanoparticles

Presently, iron oxide nanoparticles are the only ones approved for clinical use as contrast agents in magnetic resonance imaging (MRI). Even though there is a high demand for these types of nanoparticles both for clinical use as well as for research, there are difficulties in obtaining stable nanoparticles with reproducible properties. In this context, in this study, we report the obtaining by an adapted coprecipitation method of dextran-coated maghemite nanoparticles (&#612;-Fe2O3 NPs). The morphology and structure of the dextran-coated maghemite nanoparticles (&#612;-Fe2O3 NPs) were determined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The TEM and SEM micrographs highlighted the obtaining of particles of nanometric size and spherical shape morphology. Furthermore, the high-resolution transmission electron microscopy (HRTEM), as well as selected area diffraction (SAED), revealed that the obtained samples presented the structure of cubic maghemite. In this study, we also explored the effects of the co-precipitation synthesized dextran-coated maghemite nanoparticles (&#612;-Fe2O3 NPs) on the redox status of macrophages. For cytotoxicity evaluation of these NPs, murine macrophages (RAW 264.7 cell line) were exposed to different concentrations of dextran-coated maghemite nanoparticles (&#612;-Fe2O3 NPs) corresponding to 0&ndash;500 &mu;g Fe3+/mL and incubated for 24, 48, and 72 h. Intracellular iron uptake, changes in the oxidative stress parameters (reactive oxygen species production and malondialdehyde level), and the activity of antioxidant enzymes, as well as GSH concentration in cells, were evaluated after incubation with a lower (50 &mu;g Fe3+/mL) and higher (500 &mu;g Fe3+/mL) dose of NPs. The results indicated a significant decrease in RAW 264.7 cell viability after 72 h in the presence of NPs at concentrations above 25 &mu;g Fe3+/mL. An important accumulation of NPs, dependent on dose and exposure time, was detected in macrophages, but it induced only a limited raise in the oxidative status. We showed here that the antioxidant capacity of RAW 264.7 macrophages was efficient in counteracting dextran-coated maghemite nanoparticles (&#612;-Fe2O3 NPs) toxicity even at higher doses

Recursive feature elimination in random forest classification supports nanomaterial grouping

Nanomaterials (NMs) can be produced in numerous different variants of the same chemical substance. An in-depth safety assessment for each variant by generating test data will simply not be feasible. Thus, NM grouping approaches that would significantly reduce the time and amount of testing for novel NMs are urgently needed. However, identifying structurally similar NM variants remains challenging as many physico-chemical properties could be relevant. Here, we aimed at emphasizing on the value of machine learning models in the process of NM grouping by considering a case study on eleven selected, well-characterized NMs. To that end, we linked physico-chemical properties of these NMs to characterized hallmarks for inhalation toxicity. We applied unsupervised and supervised machine learning techniques to determine which combination of properties is most predictive. First, we assessed NM similarity in an unsupervised manner using principal component analysis (PCA) followed by subsequent superposition of activity labels combined with a k-nearest neighbors approach. Then, we used random forests (RFs) as a supervised machine learning technique which directly uses the knowledge on the activity class in the process of defining NM similarity. Thus, similarity was defined only on those properties showing the highest correlation with the activity and therefore had the highest discriminative power. In order to improve the performance, we then used recursive feature elimination (RFE) to delete uninformative features biasing the results. The best performance was achieved by the reduced RF model based on RFE where a balanced accuracy of 0.82 was obtained. Out of eleven different properties we determined zeta potential, redox potential and dissolution rate to have the strongest predicting impact on biological NM activity in the present dataset. Though the dataset is too small with respect to the number of NMs studied and the applicability domain is expected to be very limited due to the fact that only few material classes were covered, our study demonstrates how machine learning and feature selection methods can be implemented for identifying the most relevant physico-chemical NM properties with respect to toxicity. We suggest that once the most relevant properties have been detected in a model built on a sufficient number of different NMs and across multiple NM classes, they should obtain special emphasis in future grouping approaches.Peer Reviewe

Nanoconjugates Based on Cisplatin and Single-Walled Carbon Nanotubes for Therapy of Triple Negative Breast Cancer

Triple negative breast cancer has a phenotype characterized by the absence of progesterone and estrogen receptors and the lack of HER2 overexpression. In order to find new strategies for treatment, single-walled carbon nanotubes (SWCNT) in combination with chemotherapeutics were studied and tested as new therapeutic tools. The objective of this study was to evaluate the efficiency of SWCNT in the transport of cisplatin (CDDP) for improving its cytotoxic effects on MDA-MB-231 cells. The nanoconjugates SWCNT-COOH-CDDP were obtained by the functionalization of SWCNT with carboxyl groups (SWCNT-COOH) and conjugation with CDDP. MDA-MB-231 cells were exposed to different doses of SWCNT-COOH, SWCNT-COOH-CDDP (0.01–2 µg/mL), and CDDP (0.00632–1.26 µg/mL) for 24 and 48 h. Cellular viability was monitored through an MTT test. The level of reactive oxygen species (ROS) and reduced glutathione (GSH) were evaluated using fluorescence and spectrophotometric methods, respectively. The expressions of Nrf2, caspase-3, caspase-8, and Bid proteins were assessed by immunoblotting in the presence of 0.5 and 1 µg/mL nanoconjugates. Additionally, the effects of SWCNT-COOH-CDDP on cell migration were monitored using a wound healing assay. The cellular viability decreased and ROS level increased in a time and dose-dependent manner in the presence of nanoconjugates relative to the control. Moreover, the level of GSH rose after 24 and 48 h of exposure to 0.5 µg/mL SWCNT-COOH-CDDP, while a decrease to 78.31% was recorded after 48 h in the presence of 1 µg/mL nanoconjugates. The expression of Nrf2 decreased to 33% after 24 h of treatment with 1 µg/mL SWCNT-COOH-CDDP and increased to 80% compared to the control (100%) after 48 h. Upregulation of caspase-3 and caspase-8 and downregulation of Bid post-exposure to 1 µg/mL SWCNT-COOH-CDDP was noticed. The inhibition of cell migration was observed after 24 and 48 h of exposure to 1 µg/mL SWCNT-COOH-CDDP. In conclusion, these nanoconjugates induced apoptosis in MDA-MB-231 cells, probably by both intrinsic and extrinsic pathways, by triggering the oxidative stress mechanisms, and inhibited their migration potential

Amorphous Silica Nanoparticles Obtained by Laser Ablation Induce Inflammatory Response in Human Lung Fibroblasts

Silica nanoparticles (SiO2 NPs) represent environmentally born nanomaterials that are used in multiple biomedical applications. Our aim was to study the amorphous SiO2 NP-induced inflammatory response in MRC-5 human lung fibroblasts up to 72 hours of exposure. The intracellular distribution of SiO2 NPs was measured by transmission electron microscopy (TEM). The lactate dehydrogenase (LDH) test was used for cellular viability evaluation. We have also investigated the lysosomes formation, protein expression of interleukins (IL-1&#946;, IL-2, IL-6, IL-8, and IL-18), COX-2, Nrf2, TNF-&#945;, and nitric oxide (NO) production. Our results showed that the level of lysosomes increased in time after exposure to the SiO2 NPs. The expressions of interleukins and COX-2 were upregulated, whereas the expressions and activities of MMP-2 and MMP-9 decreased in a time-dependent manner. Our findings demonstrated that the exposure of MRC-5 cells to 62.5 &#181;g/mL of SiO2 NPs induced an inflammatory response