Effect of Curing Time on Polymerization Rate of Bulk-Fill Composite Resins

Objectives: The aim of this study was to compare polymerization depth of two bulk-fill and one conventional composite cured for different times.Methods: This in vitro experimental study was conducted on 54 composite samples (2×4×10mm) fabricated of Tetric N-Ceram bulk-fill, x-tra fil bulk-fill, and Grandio conventional composite cured for 20, 30, and 40 seconds. The microhardness of samples was measured at 0.1, 2, 2.5, 3, 3.5, 4, and 4.5mm depths using a Vickers hardness tester. The results were analyzed using ANOVA, t-test, and Tukey’s test.Results: The x-tra fil, Tetric N-Ceram and Grandio had maximum microhardness at 0.1mm depth after curing for 40 seconds. The microhardness decreased as the depth of composite increased. Microhardness of x-tra fil was higher than that of Tetric N Ceram. By increasing the curing time, the microhardness value of x-tra fil significantly increased up to 2mm depth. In Tetric N-Ceram, by increasing the curing time from 20 to 30 seconds microhardness increased significantly (P<0.05) by up to 3.5mm depth. By increase from 20 to 30 seconds, no significant change occurred in microhardness of Grandio samples at 0.1 and 2mm depths, but further increase from 30 to 40 seconds significantly increased the microhardness at all depths (P<0.05).Conclusion: The maximum microhardness was obtained for x-tra fil at 0.1mm depth following 40 seconds of curing. Microhardness in deep areas (>2mm depth) depends on the type of composite, curing time and depth. Overall, 20 seconds of curing for x-tra fil and 30 seconds for Tetric N-Ceram seem appropriate

Ultrafast nonlinear optical processes and free-carrier lifetime in silicon nanowaveguides

Abstract: We report self-consistent femtosecond studies of two-photon absorption, optical Kerreffect and free-carrier index and loss in silicon nanowaveguides using heterodyne pump-probe. Free-carrier lifetime was reduced to 33ps with only 8dB/cm added loss using proton bombardment

Chemical composition and antibacterial activity of some herbal essential oils against Streptococcus mutans

Background and aims: One of the most common chronic diseases in the world is tooth decay. A variety of bacteria are involved in this disorder of which Streptococcus mutants is the most common. Essential oils are considered as new natural compounds for use in combating drug-resistant bacteria. This study was aimed to evaluate the antibacterial activity of some essential oils prepared from Eucalyptus caesia Benth, Cuminum cyminum L. and Satureja hortensis L. on S. mutants. Methods: In this study, essential oils were extracted by hydrodistillation method. E. caesia Benth, C. cyminum L. and S. hortensis L. were characterized by using gas chromatography‒mass spectrophotometry (GC‒MS). Antibacterial activity indices including minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and zone of inhibition for the above essential oils against Streptococcus mutans were determined using broth macro-dilution and disk diffusion methods. Data analysis was performed using one-way ANOVA and Tukey test. Results:Results showed that all three extracts had antibacterial activity against S. mutants. S. hortensis L. essential oil with the lowest MIC and MBC value (13.2 and 18.4 µg/ml, respectively) and the biggest inhibition zone showed the strongest antibacterial effect against S. mutants in all exposure times and at all concentrations, compared with two other essential oils. Furthermore, C. cyminum L. essential oil had higher anti-bacterial activity against S. mutant than E. caesia Benth essential oil. Conclusions:The essential oils used in the present study with different components showed antibacterial activity (especially S. hortensis L essential oil), and therefore they can be used as a new antibacterial substance. Keywords: Dental caries, Streptococcus mutans, Essential oils, Antimicrobial

Clinical characteristics and outcomes of diabetics hospitalized for COVID-19 infection

Some debates exist regarding the association of diabetes mellitus (DM) with COVID-19 infection severity and mortality. In this study, we aimed to describe and compare the clinical characteristics and outcomes of hospitalized COVID-19 patients with and without DM. In this single-centered, retrospective, observational study, we enrolled adult patients with COVID-19 who were admitted to the Shariati hospital, Tehran, Iran, from February 25, 2020, to April 21, 2020. The clinical and paraclinical information as well as the clinical outcomes of patients were collected from inpatient medical records. A total of 353 cases were included (mean age, 61.67 years; 57.51 % male), of whom 111 patients were diabetics (mean age, 63.66 years; 55.86 % male). In comparison to those without DM, diabetic patients with COVID-19 were more likely to have other comorbidities, elevated systolic blood pressure (SBP), elevated blood sugar (BS), lower estimated glomerular filtration rate (eGFR) and elevated blood urea nitrogen (BUN). The association of DM with severe outcomes of COVID-19 infection (i.e. mechanical ventilation, median length of hospital stay and mortality) remained non-significant before and after adjustments for several factors including age, sex, body mass index (BMI), smoking status, and comorbidities. Based on our results DM has not been associated with worse outcomes in hospitalized patients for COVID-19 infection

Proceedings of the 29th EG-ICE International Workshop on Intelligent Computing in Engineering

This publication is the Proceedings of the 29th EG-ICE International Workshop on Intelligent Computing in Engineering from July 6-8, 2022. The EG-ICE International Workshop on Intelligent Computing in Engineering brings together international experts working on the interface between advanced computing and modern engineering challenges. Many engineering tasks require open-world resolution of challenges such as supporting multi-actor collaboration, coping with approximate models, providing effective engineer-computer interaction, search in multi-dimensional solution spaces, accommodating uncertainty, including specialist domain knowledge, performing sensor-data interpretation and dealing with incomplete knowledge. While results from computer science provide much initial support for resolution, adaptation is unavoidable and most importantly, feedback from addressing engineering challenges drives fundamental computer-science research. Competence and knowledge transfer goes both ways. &nbsp

Proceedings of the 29th EG-ICE International Workshop on Intelligent Computing in Engineering

This publication is the Proceedings of the 29th EG-ICE International Workshop on Intelligent Computing in Engineering from July 6-8, 2022. The EG-ICE International Workshop on Intelligent Computing in Engineering brings together international experts working on the interface between advanced computing and modern engineering challenges. Many engineering tasks require open-world resolution of challenges such as supporting multi-actor collaboration, coping with approximate models, providing effective engineer-computer interaction, search in multi-dimensional solution spaces, accommodating uncertainty, including specialist domain knowledge, performing sensor-data interpretation and dealing with incomplete knowledge. While results from computer science provide much initial support for resolution, adaptation is unavoidable and most importantly, feedback from addressing engineering challenges drives fundamental computer-science research. Competence and knowledge transfer goes both ways. &nbsp

Characterization of the archaebacterial ortholog of the processing body subunit Winnebago/Growl

Because the transcriptional machinery is inactive throughout late stages of oogenesis and early stages of embryogenesis, the initial development of the embryo is driven by post-transcriptional regulation of maternally deposited mRNA. In Drosophila, this post-transcriptional regulation occurs at specialized sites called P- bodies. While P bodies contain proteins required for mRNA degradation, translational control, and microRNA processing, the complete composition of the P body is unknown. Recent work on the biochemistry of the P body has identified a novel protein of unknown function called Winnebago. Winnebago contains an atypical conserved ATPase motif homologous with the cyclo-ligase human methenyltetrahydrofolate synthetase (MTHFS) and a conserved RNA recognition motif suggesting that Winnebago may be a novel RNA modifying enzyme. Consistent with this, the substrate binding site of the Winnebago and its archaebacterial homologs are not conserved with the human MTHFS, indicating that Winnebago has a unique class of substrate. In this study, Swinn, the Winnebago homolog from Sulfolobus, was purified and it was demonstrated that it is an ATPase. We also found that Swinn does not use the normal substrates of MTHFS, arguing that it acts on a novel class of cyclo-ligase substrates. This work lays the groundwork for future studies to identify the substrate of the Winnebago family of ATPases and their role in RNA regulatio

Characterization of the archaebacterial ortholog of the processing body subunit Winnebago/Growl

Because the transcriptional machinery is inactive throughout late stages of oogenesis and early stages of embryogenesis, the initial development of the embryo is driven by post-transcriptional regulation of maternally deposited mRNA. In Drosophila, this post-transcriptional regulation occurs at specialized sites called P- bodies. While P bodies contain proteins required for mRNA degradation, translational control, and microRNA processing, the complete composition of the P body is unknown. Recent work on the biochemistry of the P body has identified a novel protein of unknown function called Winnebago. Winnebago contains an atypical conserved ATPase motif homologous with the cyclo-ligase human methenyltetrahydrofolate synthetase (MTHFS) and a conserved RNA recognition motif suggesting that Winnebago may be a novel RNA modifying enzyme. Consistent with this, the substrate binding site of the Winnebago and its archaebacterial homologs are not conserved with the human MTHFS, indicating that Winnebago has a unique class of substrate. In this study, Swinn, the Winnebago homolog from Sulfolobus, was purified and it was demonstrated that it is an ATPase. We also found that Swinn does not use the normal substrates of MTHFS, arguing that it acts on a novel class of cyclo-ligase substrates. This work lays the groundwork for future studies to identify the substrate of the Winnebago family of ATPases and their role in RNA regulatio

Price forecasting in electricity markets and smart grids

Bibliography: p. 140-154