Patients' knowledge about dental emergencies, COVID-19 transmission, and required preparations in dental settings.

INTRODUCTION: The Coronavirus disease 2019 (COVID-19) pandemics negatively affected the delivery of dental care. The study objective was to assess the knowledge of emergency dental treatments, the transmission routes of COVID-19 in the dental settings, necessary precautions to prevent disease transmission, and the associations between demographic factors and the mentioned domains among Iranian dental patients. METHODS: This was a cross-sectional study conducted in October 2021. A systematic random sampling approach was used to select 244 participants who had sought services at the dental clinic of Tehran University of Medical Sciences before and during the pandemic. Data was collected using a combination of interviewer-administered and self-administered questionnaire. Three backward stepwise multiple logistic regression analyses were conducted to determine the associations between background factors (age, sex, education level, living status, history of dental visits, history of COVID-19 vaccination, and past COVID-19 infection) and knowledge about emergency dental treatments, knowledge about COVID-19 transmission routes, and knowledge about necessary preparations in dental settings. RESULTS: The mean (SD) scores for knowledge of emergency dental treatments, COVID-19 transmission routes, and essential preparations in dental settings measured on a 100-point scale were 77 (15.4), 84.2 (12.3), and 93.3 (12.1), respectively. Good knowledge of emergency dental treatments was associated with being under 55 years old (p = 0.03). Good knowledge of COVID-19 transmission routes was associated with living with individuals at a high risk of COVID-19 (p = 0.014) and having received the COVID-19 vaccine (p = 0.013). After adjusting for age, among participants aged 30 years and older, good knowledge of necessary preparations in dental settings was associated with being female (p = 0.012) and having received the COVID-19 vaccine (p = 0.001). CONCLUSIONS: Patients who sought care at the dental clinic of Tehran University of Medical Sciences had good knowledge about the transmission routes of COVID-19 and the required preparations in dental settings, and limited knowledge about dental emergency treatments.

Review of sustainable, eco-friendly, and conductive polymer nanocomposites for electronic and thermal applications: current status and future prospects.

Biodegradable polymer nanocomposites (BPNCs) are advanced materials that have gained significant attention over the past 20 years due to their advantages over conventional polymers. BPNCs are eco-friendly, cost-effective, contamination-resistant, and tailorable for specific applications. Nevertheless, their usage is limited due to their unsatisfactory physical and mechanical properties. To improve these properties, nanofillers are incorporated into natural polymer matrices, to enhance mechanical durability, biodegradability, electrical conductivity, dielectric, and thermal properties. Despite the significant advances in the development of BPNCs over the last decades, our understanding of their dielectric, thermal, and electrical conductivity is still far from complete. This review paper aims to provide comprehensive insights into the fundamental principles behind these properties, the main synthesis, and characterization methods, and their functionality and performance. Moreover, the role of nanofillers in strength, permeability, thermal stability, biodegradability, heat transport, and electrical conductivity is discussed. Additionally, the paper explores the applications, challenges, and opportunities of BPNCs for electronic devices, thermal management, and food packaging. Finally, this paper highlights the benefits of BPNCs as biodegradable and biodecomposable functional materials to replace traditional plastics. Finally, the contemporary industrial advances based on an overview of the main stakeholders and recently commercialized products are addressed.

The power of one clean qubit in supervised machine learning.

This paper explores the potential benefits of quantum coherence and quantum discord in the non-universal quantum computing model called deterministic quantum computing with one qubit (DQC1) in supervised machine learning. We show that the DQC1 model can be leveraged to develop an efficient method for estimating complex kernel functions. We demonstrate a simple relationship between coherence consumption and the kernel function, a crucial element in machine learning. The paper presents an implementation of a binary classification problem on IBM hardware using the DQC1 model and analyzes the impact of quantum coherence and hardware noise. The advantage of our proposal lies in its utilization of quantum discord, which is more resilient to noise than entanglement.

Synthesis and characterization of chitosan/collagen/polycaprolactone hydrogel films with enhanced biocompatibility and hydrophilicity for artificial tendon applications.

Regenerative medicine confronts various obstacles, such as creating and advancing biomaterials. Besides being safe, such materials should promote cellular activity. Polycaprolactone (PCL) has numerous medical applications as an engineering material. However, these polymers lack hydrophilicity. Herein, chitosan (CS)/collagen (COL)/polycaprolactone hydrogel films (CSCPs) were synthesized with different weight ratios of PCL; specifically, CS/COL (CSC): PCL content of 1:3, 1:6, and 1:9. For this purpose, novel COL immobilization on CS was performed via covalent attachment. Following the addition of PCL to CSC hydrogel, the resulting CSCP hydrogel films were characterized using tensile measurements, TGA, XRD, FTIR, and FE-SEM. A greater PCL content increases the elongation at break from 134.8 to 369.5 % and the tensile strength of the hydrogel films from 4.8 to 18.4 MPa. The hydrophobicity of prepared specimens was assessed through water absorption and contact-angle tests. For CSCP3 to CSCP9, the water contact angle increased from 61.03° to 70.82°. After 48 days, CSCP6 and CSCP9 hydrogel films demonstrated a slow rate of degradation, losing <15 % of their weight. Moreover, all three types of hydrogel films exhibited high biocompatibility (higher than 95 % after three days), as confirmed by the MTT assay. The hemolysis rates of CSCP hydrogel films were <2 %, which could be deemed safe for contact with a blood environment. The presence of no costly and bio-based crosslinking agents and desired characteristics for tissue engineering applications suggest that CSCP hydrogel films may be promising candidates for use in artificial tendons.

Examining rheological behavior of CeO2-GO-SA/10W40 ternary hybrid nanofluid based on experiments and COMBI/ANN/RSM modeling.

In this study, the rheological behavior and dynamic viscosity of 10W40 engine oil in the presence of ternary-hybrid nanomaterials of cerium oxide (CeO2), graphene oxide (GO), and silica aerogel (SA) were investigated experimentally. Nanofluid viscosity was measured over a volume fraction range of VF = 0.25-1.5%, a temperature range of T = 5-55 °C, and a shear rate range of SR = 40-1000 rpm. The preparation of ternary-hybrid nanofluids involved a two-step process, and the nanomaterials were dispersed in SAE 10W40 using a magnetic stirrer and ultrasonic device. In addition, CeO2, GO, and SA nanoadditives underwent X-ray diffraction-based structural analysis. The non-Newtonian (pseudoplastic) behavior of ternary-hybrid nanofluid at all temperatures and volume fractions is revealed by analyzing shear stress, dynamic viscosity, and power-law model coefficients. However, the nanofluids tend to Newtonian behavior at low temperatures. For instance, dynamic viscosity declines with increasing shear rate between 4.51% (at 5 °C) and 41.59% (at 55 °C) for the 1.5 vol% nanofluid. The experimental results demonstrated that the viscosity of ternary-hybrid nanofluid declines with increasing temperature and decreasing volume fraction. For instance, assuming a constant SR of 100 rpm and a temperature increase from 5 to 55 °C, the dynamic viscosity increases by at least 95.05% (base fluid) and no more than 95.82% (1.5 vol% nanofluid). Furthermore, by increasing the volume fraction from 0 to 1.5%, the dynamic viscosity increases by a minimum of 14.74% (at 5 °C) and a maximum of 35.94% (at 55 °C). Moreover, different methods (COMBI algorithm, GMDH-type ANN, and RSM) were used to develop models for the nanofluid's dynamic viscosity, and their accuracy and complexity were compared. The COMBI algorithm with R2 = 0.9995 had the highest accuracy among the developed models. Additionally, RSM and COMBI were able to generate predictive models with the least complexity.

Numerical investigation the hydrodynamic parameters of the flow in a wavy corrugated channel using different turbulence models.

In this research, turbulent flow numerical models in a wavy channel were investigated. The studied channel is simulated in two dimensions and symmetrically in the range of Reynolds numbers from Re=10,000 to 80,000. The significant cause of this research is to investigate and determine the appropriate method for estimating the behavior of turbulent flow in a wavy channel. In this research, the behavior of turbulent flow in a wavy channel will be simulated in 7 different ways, which are k-ω SST, k-ϵ RN, k-ϵ Realizable, k-ϵ Standard, k-ω Standard, Reynolds stress and Spalart-Allmaras. The findings of this research show that the impacts of the presence of flow viscosity (friction) and the presence of adverse pressure gradients are factors that strongly affect the velocity profiles in the upstream areas of the corrugated section. Among the studied models, due to better compatibility and guessing of flow and hydrodynamic properties, k-ω SST methods and Reynolds and Spalart-Allmaras stress are introduced as the best methods for such geometries. On the other hand, increasing the accuracy of other turbulence methods is related to the flow physics and geometric structure of each problem. In this research, the hydrodynamic parameters of the flow such as pressure drop, skin friction factor, and dynamic pressure drop coefficient and vortex contours, and pressure are plotted and described.

Rheological Behavior of SAE50 Oil-SnO2-CeO2 Hybrid Nanofluid: Experimental Investigation and Modeling Utilizing Response Surface Method and Machine Learning Techniques.

In this study, for the first time, the effects of temperature and nanopowder volume fraction (NPSVF) on the viscosity and the rheological behavior of SAE50-SnO2-CeO2 hybrid nanofluid have been studied experimentally. Nanofluids in NPSVFs of 0.25% to 1.5% have been made by a two-step method. Experiments have been performed at temperatures of 25 to 67 °C and shear rates (SRs) of 1333 to 2932.6 s-1. The results revealed that for base fluid and nanofluid, shear stress increases with increasing SR and decreasing temperature. By increasing the temperature to about 42 °C at a NPSVF of 1.5%, about 89.36% reduction in viscosity is observed. The viscosity increases with increasing NPSVF about 37.18% at 25 °C. In all states, a non-Newtonian pseudo-plastic behavior has been observed for the base fluid and nanofluid. The highest relative viscosity occurs for NPSVF = 1.5%, temperature = 25 °C and SR = 2932.6 s-1, which increases the viscosity by 37.18% compared to the base fluid. The sensitivity analysis indicated that the highest sensitivity is related to temperature and the lowest sensitivity is related to SR. Response surface method, curve fitting method, adaptive neuro-fuzzy inference system and Gaussian process regression (GPR) have been used to predict the dynamic viscosity. Based on the results, all four models can predict the dynamic viscosity. However, the GPR model has better performance than the other models.

Evaluation of antimicrobial photodynamic therapy with toluidine blue against Enterococcus faecalis: Laser vs LED.

AIM: This study aimed to compare the antibacterial effect of antimicrobial photodynamic therapy (aPDT) by use of light emitting diode (LED) and diode laser light sources with toluidine blue (TBO) photosensitizer on Enterococcus faecalis (E. faecalis) biofilm in root canals of extracted single-canal human teeth. METHODS: Eighty-five sound human single-canal teeth were chosen for this study and standardized to have 15 mm of root length. The root canals were prepared with ProTaper rotary files and inoculated and incubated with E. faecalis for one week. Samples were divided into five experimental (n = 15) groups of PDT with TBO/LED, TBO/diode laser, LED, TBO and diode laser and one negative (NaOCl) and one positive (no treatment) control group. Dentin chip samples were collected from inside the canals using size 40 hedstrom file. The number of colony forming units (CFUs) in each group was calculated. RESULTS: Irrespective of the light source used for activation of photosensitizer (diode or LED), PDT was significantly more effective than other experimental groups (P < 0.001). No significant difference was noted between aPDT with diode laser or LED (P > 0.05). No significant difference was noted in colony count among other groups (LED, TBO, diode; P > 0.05). CONCLUSION: The results showed that aPDT significantly decreased residual bacteria in the canal. Thus, it may be used as an adjunct for root canal disinfection. Both diode and LED are suitable light sources for this purpose and can be used alternatively.

Development of osteogenic chitosan/alginate scaffolds reinforced with silicocarnotite containing apatitic fibers.

Porous composite scaffolds of chitosan-alginate (CH-AL) reinforced by biphasic calcium phosphate fibers containing silicon (Si) were prepared using the freeze-drying method. The fibers were synthesized using a homogenous precipitation method with differing reaction times and were characterized by XRD, FTIR, SEM, and ICP-OES. Fibers produced with no Si incorporation using two different reaction times of 4 d and 8 d comprised two phases of hydroxyapatite (∼93-96 wt%) and ß-tricalcium phosphate (ß-TCP). No new phases were observed by adding 0.8 wt% of Si during 4 d of precipitation. However, the addition of Si to fibers synthesized within 8 d under reflux conditions produced biphasic fibers with 1.9 wt% Si which consisted of a new phase of silicocarnotite (∼94 wt%) associated with the ß-TCP phase. The whisker-like fibers were 10-200 µm in length and 0.2-5 µm in width. The physicochemical, mechanical, and biological properties of composite scaffolds fabricated by adding different fiber contents and types were investigated. The scaffolds exhibited favorable microstructures with a high porosity (66-88%) and the interconnected pores varied in size between 40 and 250 µm. Scaffolds containing silicocarnotite showed a significant improvement in their mechanical properties and in vitro bioactivity (using SBF testing and characterization of the apatite layer by ATR-FTIR and SEM/EDS) as well as proliferation, mineralization and adhesion of MG63 cells, when evaluated by MTT assay, alkaline phosphatase, and SEM. Scaffolds reinforced with silicocarnotite fibers also exhibited better mechanical properties and water uptake, compared to ones containing incorporated fibers made of Si. Composite scaffolds reinforced by 50 wt% fibers precipitated after 8 d were superior in terms of their mechanical properties and achieved a compressive strength and modulus of 272 kPa and 4.9 MPa, respectively, which is 400% greater than CH-AL scaffolds. The results indicate that the addition of Si into biphasic fibers, leading to the formation of silicocarnotite, makes silicocarnotite a potential candidate for the bioactive reinforcement of composite scaffolds for bone tissue engineering.

UiO-66 metal organic framework nanoparticles loaded carboxymethyl chitosan/poly ethylene oxide/polyurethane core-shell nanofibers for controlled release of doxorubicin and folic acid.

Doxorubicin (DOX) and folic acid (FA) were incorporated into the UiO-66 metal organic framework (MOF) and following were loaded into the carboxymethyl chitosan/poly ethylene oxide (PEO)/polyurethane core-shell nanofibers for controlled release of DOX and FA toward MCF-7 cells death. The synthesized nanocarriers were characterized using TEM, XRD, and SEM analysis. The drug loading efficiency and release profiles of DOX/MOF and FA/MOF from synthesized nanofibers have been investigated. The fitting of kinetic data by the pharmacokinetic models demonstrated the non-Fickian diffusion from nanofibers and Fickian diffusion from core-shell fibers. The cytotoxicity of synthesized nanofibers toward MCF-7 cancer cells was evaluated using DAPI staining, MTT assay and flow cytometry tests to investigate the simultaneous use of DOX and FA in the nanofibrous matrix for MCF-7 cells death in vitro. The maximum cell death using DOX-FA loaded-core-shell fibers produced by coaxial electrospinning method under 0.3, 0.5 and 0.8 mLh-1 shell flow rates were found to be 82 ± 0.7, 83 ± 0.5 and 87 ± 0.5% after 168, 240 and 240 h, respectively. The cytotoxicity results indicated that the co-delivery of DOX and FA into the core-shell fibers could be widely used for various cancers treatment.

Complementary Diagnostic Value of Heart Type Fatty Acid-binding Protein in Early Detection of Acute Myocardial Infarction.

BACKGROUND: Heart-type fatty acid-binding protein (H-FABP) is a novel biomarker for myocardial injury. We compared the use of H-FABP with serum levels of cardiac troponin-T (cTnT) and creatine kinase-MB (CK-MB) in the diagnosis of patients suspicious to acute myocardial infarction (AMI). METHODS: From October 2013 to December 2014, 182 consecutive patients suspicious to acute coronary syndrome were enrolled in this study, who presented within the past 6 hours from the onset of symptoms. Venous blood samples were drawn at baseline to measure serum biochemistry, high-sensitive cardiac troponin T (hs-cTNT), creatine kinase-MB, and H-FABP, and the measurements were repeated after 8 hours. The patients were categorized into 3 groups based on the baseline and second measurements of cTnT and general characteristics, and changes of H-FABP levels were then compared between the groups. Sensitivity and specificity of H-FABP in predicting the presence of AMI was calculated. RESULTS: A total of 91 patients had AMI. Changes of H-FABP through time were also significantly different between the AMI and non-AMI patients (P < 0.001). A cutoff point of 7.15 for H-FABP could predict AMI with a sensitivity of 51.5%, specificity of 96.3%, and diagnostic accuracy of 68.3%. The area under the receiver operating characteristic curve for H-FABP at 8 hours was 79.4% (95% confidence interval: 73.0-85.9; P < 0.001). Positive predictive value and negative predictive value for H-FABP were 85% and 60%, respectively. CONCLUSIONS: H-FABP can be used as an additional cardiac biomarker in the diagnosis of AMI.