The Comparative Evaluation of the Post-Antimicrobial Effect of MTAD® and 2% Chlorhexidine against Enterococcus faecalis of Permanent Teeth with Necrotic Pulp

AIM: Enterococcus faecalis is one of the most resistant bacteria in necrotic teeth. That’s why the goal of this study was to determine the post-antibiotic effect of MTAD®& 2% Chlorhexidine® as root canal irrigating solution on clinical isolates of E. faecalis from infected root canals of permanent teeth, using the spectrophotometric technique. MATERIAL AND METHODS: The antibacterial efficacy of Chloramphenicol 30 mcg, Nitrofurantoin 300 mcg, Vancomycin 5 mcg, Amoxicillin/clavulanic acid 30 mcg and Ofloxacin 5 mcg against E. faecalis was compared using the Disc diffusion method. Patients were selected for this study with permanent necrotic teeth. The sterile paper point was inserted inside the infected root canal and left for 60 seconds; to obtain the microbiological sample. Postantibiotic effect of MTAD® and 2% Chlorohexidine® on E. faecalis was compared. The absorbance of bacterial growth was examined for both irrigating solutions during the first 10 hours with an hour interval, and then tested at 48, 72, 96 up to 240 hours. RESULTS: The results showed that during the first 10 hours, MTAD® showed immediate antibacterial effect and maintained its higher antibacterial activity than 2% chlorohexidine®. After 48, 72, 96 and 240 hours, both MTAD® and 2% chlorohexidine® showed the same prolonged action of post-antibiotic effect against E. faecalis with a non-significant difference. According to Antibiotic sensitivity, the results revealed MTAD® is the most effective antimicrobial drug, showing the highest zone of inhibition, followed by 2% Chlorhexidine and Nitrofurantoin 300 mcg which showed the same inhibitory activity CONCLUSION: From the current study, it can be concluded that MTAD® has a strong bactericidal effect against E. faecalis and showed the highest zone of inhibition

Shape-dependent antibacterial activity of silver nanoparticles on Escherichia.coli and Enterococcus.faecium bacterium

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Silver nanoparticles (AgNPs) have been shown to exhibit strong antibacterial activity against both Gram-positive bacteria and Gram-negative bacteria including antibiotic resistant strains. The antibacterial activity of AgNPs against Escherichia coli and Streptococcus mutans (S. Mutans) has been reported and found to be size dependent. This study aims to compare the bactericidal effect of different shaped AgNPs (spherical and truncated octahedral) against E.coli and E.faecium. The antimicrobial activity of a range of concentrations (50, 100, 1000μg/ml) was determined over 24 hours using both optical density and viable counts. Truncated octahedral AgNPs (AgNoct) were found to be more active when compared with spherical AgNPs (AgNS). The difference in shape resulted in differences in efficacy which may be due to the higher surface area of AgNOct compared to AgNS, and differences in active facets and surface energies, with AgNPs having a bacteriostatic effect and AgNOct is being bactericidal after 4 hours. The results suggest that AgNPs can be used as effective growth inhibitors in different microorganisms, rendering them applicable tovarious medical devices and antimicrobial control systems

Intravitreal triamcinolone acetonide injection for macular edema due to central retinal vein occlusion persisting despite multiple intravitreal bevacizumab injections.

PURPOSE: To evaluate the response to intravitreal triamcinolone acetonide for macular edema persisting or recurring despite multiple intravitreal bevacizumab (IVB) treatments for central retinal vein occlusion (CRVO). METHODS: Retrospective interventional case series of 21 eyes with CRVO from 21 patients who were diagnosed with persistent or recurrent macular edema secondary to CRVO and treated with 0.1mL (4mg) intravitreal triamcinolone acetonide (IVTA) after initial treatment with 3 or more IVB injections. Anatomic and visual responses were the study primary outcomes. RESULTS: Mean logarithm of the minimum angle of resolution visual acuity was 1.19 (20/316) immediately before IVTA injection, and improved to 1.04 (20/219) 1 month after IVTA administration (P=0.003). The mean central macular thickness on optical coherence tomography decreased from 533.4 μm immediately before IVTA to 327.9 μm after IVTA injection (P CONCLUSIONS: Intravitreal triamcinolone acetonide appears to improve vision and reduce persistent or recurrent macular edema secondary to CRVO despite multiple bevacizumab injections

SPEAKING CHALLENGES THAT ENCOUNTER 2ND AND 3RD YEAR EFL UNIVERSITY STUDENTS

This research investigated the common problems and difficulties that face 2nd and 3rd year undergraduate students in developing their speaking skills. The qualitative approaches (interview and observation) were used as methods of collecting data of this study. Four classes were involved in the classroom observation, twenty students from this cohort and four teachers were interviewed. Some of the difficulties which were introduced in this study were related to the poor classroom conditions and methods that teachers employ in teaching speaking skills. Some other difficulties were related to pronunciation, including adding extra vowels and intonation and stress. Furthermore, there were other difficulties regarding the lack of vocabulary, which lead the students to avoid practicing their problems, have been provided in this study. The findings of this study are important as they represent the most influential factors which appear to be responsible for the problems of developing 2nd and 3rd year under- graduate students speaking skills. Recognition of the problems outlined in the first step of this study in order to supply appropriate solutions for overcoming these difficulties. In addition, these findings draw attention towards the importance of helping both the foreign language teachers and students to change their perspective about teaching and learning English speaking skills

Chemical Synthesis of Copper Nanospheres and Nanocubes and Their Antibacterial Activity Against Escherichia coli and Enterococcus sp.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. The fulltext can also be viewed at this link: http://rdcu.be/mVXDThe interest in synthesising inorganic nanomaterials for biological applications has increased in recent years, especially for antibacterial purposes. In the present study, spherical and cube-shaped copper nanoparticles were synthesised by a chemical reduction method and their efficacy as antimicrobial agents against both Gram-negative (Escherichia coli) and Gram-positive (Enterococcus sp.) organisms investigated. The nanoparticles were characterised using ultraviolet/visible spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction. Copper nanocubes were found to be more antimicrobial when compared with copper nanospheres, and it is postulated that whilst both sets of nanoparticles have similar total surface areas, the different shapes have different active facets and surface energies, which may lead to differing bactericidal behaviour

Knowledge of mothers about use of fissure sealant therapy and professional fluoride therapy among children in Saudi Arabia

Purpose: To evaluate mothers’ knowledge of the use of fissure sealant (FS) and topical fluoride (TF) therapy among children aged between 7 to 12 years in Saudi Arabia. Methods: In this cross-sectional study, participants (n = 350) were selected based on simple random sampling method from the mothers’ of children aged from 7 to 12 years old, attending outpatient pediatric dental clinics in College of Dentistry King Khalid University, Abha, Saudi Arabia. Results: The age group of mothers included are as follows: 31.7 % in 20 - 30 years age group, 53.1 % in 31 - 40 years age range, and 15.1 % in 41 - 50 years. On FS therapy benefits in the prevention of caries in children, 22 % responded that it was beneficial. When participants were asked regarding FS wearing out easily after application on the tooth, 8 % agreed while 13.4 % disagreed. A majority of mothers (40.9 %) agreed that TF therapy prevents caries, while 47.7 % stated that they brush twice daily with fluoride toothpaste. The mothers that disagreed that fluoride gel is recommended only for children, not for adults were 32.9 %. When the mothers were asked about the benefit of fluoride if its cost is taken into consideration, 46.6 % disagreed that fluoride gel was worth its cost, while 22.3 % took the opposite view. Conclusion: Positive knowledge of FS and TF therapy have been observed among mothers. However, mothers demonstrated greater positive knowledge of TF therapy than FS therapy

Quantifying the Importance of Latent Features in Neural Networks

The susceptibility of deep learning models to adversarial examples raises serious concerns over their application in safety-critical contexts. In particular, the level of understanding of the underlying decision processes often lies far below what can reasonably be accepted for standard safety assurance. In this work, we provide insights into the high-level representations learned by neural network models. We specifically investigate how the distribution of features in their latent space changes in the presence of distortions. To achieve this, we first abstract a given neural network model into a Bayesian Network, where each random variable represents the value of a hidden feature. We then estimate the importance of each feature by analysing the sensitivity of the abstraction to targeted perturbations. An importance value indicates the role of the corresponding feature in underlying decision process. Our empirical results suggest that obtained feature importance measures provide valuable insights for validating and explaining neural network decisions

The metabolomic analysis of five Mentha species: cytotoxicity, anti-Helicobacter assessment, and the development of polymeric micelles for enhancing the anti-Helicobacter activity

Mentha species are medicinally used worldwide and remain attractive for research due to the diversity of their phytoconstituents and large therapeutic indices for various ailments. This study used the metabolomics examination of five Mentha species (M. suaveolens, M. sylvestris, M. piperita, M. longifolia, and M. viridis) to justify their cytotoxicity and their anti-Helicobacter effects. The activities of species were correlated with their phytochemical profiles by orthogonal partial least square discriminant analysis (OPLS-DA). Tentatively characterized phytoconstituents using liquid chromatography high-resolution electrospray ionization mass spectrometry (LC-HR-ESI-MS) included 49 compounds: 14 flavonoids, 10 caffeic acid esters, 7 phenolic acids, and other constituents. M. piperita showed the highest cytotoxicity to HepG2 (human hepatoma), MCF-7 (human breast adenocarcinoma), and CACO2 (human colon adenocarcinoma) cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. OPLS-DA and dereplication studies predicted that the cytotoxic activity was related to benzyl glucopyranoside-sulfate, a lignin glycoside. Furthermore, M. viridis was effective in suppressing the growth of Helicobacter pylori at a concentration of 50 mg mL−1. OPLS-DA predicted that this activity was related to a dihydroxytrimethoxyflavone. M. viridis extract was formulated with Pluronic® F127 to develop polymeric micelles as a nanocarrier that enhanced the anti-Helicobacter activity of the extract and provided minimum inhibitory concentrations and minimum bactericidal concentrations of 6.5 and 50 mg mL−1, respectively. This activity was also correlated to tentatively identified constituents, including rosmarinic acid, catechins, carvone, and piperitone oxide

An efficient reusable perylene hydrogel for removing some toxic dyes from contaminated water

From Wiley via Jisc Publications RouterHistory: received 2020-11-24, rev-recd 2021-01-05, accepted 2021-01-11, pub-electronic 2021-02-03, pub-print 2021-09Article version: VoRPublication status: PublishedAbstract: The synthesis of adsorbents that meet the need for large‐scale production at relatively low cost and are capable of removing anionic and cationic toxic dyes from aqueous solutions, with high sorption capacity and reusability, is urgently needed from an environmental and industrial viewpoint. In this context the identification of hydrogels that remove dyes efficiently under ambient conditions and at near‐neutral pH without the necessity of pre‐treatment is an imperative. In this study we report the preparation of two hydrogels using the redox polymerisation of acrylamide, hydroxyethylmethacrylate (HEMA) and N‐isopropylacrylamide (H1) and acrylamide, HEMA, N‐isopropylacrylamide and perylene‐5‐ylpent‐3‐yne‐2‐methylprop‐2‐enoate‐co‐2‐methyl‐2‐(prop‐2‐enoylamino)propane‐1‐sulfonic acid (PePnUMA‐co‐AMPS) (H2). These hydrogels proved to be effective for the removal of methylene blue (MB), fuchsin acid (FA) and Congo Red (CR) from aqueous solution at near‐neutral pH where their adsorption behaviour was in keeping with the Langmuir model having qmax values of 769.2 mg g−1 (MB), 1666.7 mg g−1 (FA) and 2358.2 mg g−1 (CR). The adsorption of MB and FA by these hydrogels follows pseudo‐first‐order kinetics, whilst the adsorption of CR follows pseudo‐second‐order kinetics. Detailed thermodynamic analysis indicated that the dye–adsorbent interaction is primarily one of physisorption in nature. Finally, desorption studies carried out in 1.0 mol L–1 NaClO4 indicated that these adsorbents could be recycled at least four times using a variety of dyes while maintaining their mechanical properties. © 2021 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry