Physical properties and bioactivity of Aloe vera modified tricalcium silicate-based cement

Objective: This study compares the physical properties and bioactivity of tricalcium silicate-based cement (Matreva MTA) modified with various concentrations of Aloe vera (AV) solutions and Biodentine cement. Methods: Sixty discs were prepared, and divided into 5 groups (12 discs each) based on the estimated materials: group I: Biodentine, group II: Matreva MTA, group III: Matreva MTA with 10% AV, group IV: Matreva MTA with 20% AV and group V: Matreva MTA with 30% AV. The flow and setting time were assessed following ISO standard 6876:2012 and American Society for Testing and Materials (ASTM) standard C266-21, respectively. The in-vitro bioactivity was evaluated after 1, 14, and 28 days of immersion in Hank\u27s balanced salt solution (HBSS) including pH, calcium ion release, and apatite formation. All data were statistically analyzed. Results: Increasing the AV concentration added to Matreva MTA from 0 to 30% decreased the flow and setting time. Significant high mean pH and calcium ion release values were observed for 20 and 30% AV-modified Matreva MTA cement at 14 and 28 days (P≤ 0.05). Environmental scanning electron microscope/ energy-dispersive X-ray spectroscopy (ESEM/EDX) analysis confirmed calcium phosphate nucleation on the surfaces of 20 and 30% AV-modified Matreva MTA cements after immersion in HBSS. Conclusion: Addition of 20 and 30% AV solutions to Matreva MTA reduced the setting time and improved the handling characteristics as well as the in-vitro bioactivity, resembling the qualities of Biodentine. Both AV-modified Matreva MTA and Biodentine cements had extended alkalinizing activity and calcium ion release. Clinical relevance: AV-modified Matreva MTA can be considered a promising biomaterial for different endodontic applications

An Adaptive Protection Scheme for Coordination of Distance and Directional Overcurrent Relays in Distribution Systems Based on a Modified School-Based Optimizer

This paper presents an adaptive protection scheme (APS) for solving the coordination problem that deals with coordination directional overcurrent relays (DOCRs) and distance relays second zone time, in relation to coordination with DOCRs. The coordination problem becomes more complex with the impact of renewable energy sources (RES) when added to the distribution grid. This leads to a change in the grid topology, caused by the on/off states of the distribution generators (DG). The frequency of topological changes in distribution grids poses a challenge to the power system’s protection components. The change in the state of DGs leads to malfunction in reliability and miscoordination between protection relays, since that causes a direct effect to the short circuit currents. This paper used the school-based optimization (SBO) algorithm, which simulates the educational process, in order to deal with coordination problems. That algorithm is modified (MSBO) by modified both learning and teaching processes. The IEEE 8-bus test system and IEEE 14-bus distribution network are used to validate the proposed coordination system’s effectiveness when dealing with the coordination process between distance and DOCRs, at both the near- and far-end in the typical topological grid and with DGs in working order

Cathine and cathinone disposition kinetics and neurotransmitter profile in several organs of rats exposed to a single dose of Catha edulis (Vahl) Forssk. ex Endl. extract

Catha edulis (Vahl) Forssk. ex Endl. (Khat) is a stimulant plant that contains cathine and cathinone, which its abuses induce euphoria, alertness, and motor activity. Since the toxicokinetics of these substances remain unclear, this study was carried out to investigate the disposition kinetics of cathine and cathinone, the neurotransmitter profile, following a single dose of C. edulis extract in rats. Twenty-four adult male Wistar albino rats (250-300 g) were randomly selected and divided into six groups of four rats each. All groups received a single oral dose of 2,000 mg/kg body weight, and blood and tissue samples from the brain, lung, heart, liver, and kidney were obtained at intervals of 0.5, 1, 2.5, 5, 12, and 24 h. The cathine and cathinone concentrations were identified and quantified using ion trap ultra-high performance liquid chromatography (HPLC-IT/MS). The neurotransmitter profile was detected using the quadrupole time of flight UPLC-QTOF/MS method. The lung, liver, and heart tissues attained the highest levels of cathine, while the highest level of cathinone was determined in the heart. Cathine and cathinone concentrations in the blood and heart peaked at 0.5 h. The concentrations peaked in the brain 2.5 h later, indicating that the heart had an immediate effect, whereas the brain had a longer-lasting one. They have longer half-lives (2.68 and 5.07 h, respectively) and may remain in the brain for longer durations (3.31 and 2.31 h, respectively). The neurotransmitters epinephrine, dopamine, norepinephrine, and serotonin were detected in a delayed, prolonged and organ-specific manner. Cathine and cathinone were deposited in considerable concentrations in all tissues analyzed, with the highest Cmax in the lung and Tmax in the heart tissues but not in the brain. In addition, neurotransmitters such as adrenaline, dopamine, norepinephrine, and serotonin were differentially detected in all tested samples in a organ-specific fashion. More study is needed to identify cathine and cathinone's effects on neurotransmitter profiles. Nevertheless, these findings provided a further basis for experimental, clinical, and forensic investigations

Sentiment analysis algorithms and applications: A survey

Sentiment Analysis (SA) is an ongoing field of research in text mining field. SA is the computational treatment of opinions, sentiments and subjectivity of text. This survey paper tackles a comprehensive overview of the last update in this field. Many recently proposed algorithms' enhancements and various SA applications are investigated and presented briefly in this survey. These articles are categorized according to their contributions in the various SA techniques. The related fields to SA (transfer learning, emotion detection, and building resources) that attracted researchers recently are discussed. The main target of this survey is to give nearly full image of SA techniques and the related fields with brief details. The main contributions of this paper include the sophisticated categorizations of a large number of recent articles and the illustration of the recent trend of research in the sentiment analysis and its related areas

Characterization of fretting wear of cobalt-based superalloys at high temperature for aero-engine combustor components

Cobalt-based superalloys are used in aero-engine combustor components due to their high strength and wear resistance at elevated temperatures. The objective of this investigation is to study the role of the surface oxide formed during the fretting process on the tribological behavior of this class of materials, at temperatures up to 550\ub0C. The investigation, which was carried out using a specially designed tribometer, showed that the wear coefficient and the coefficient of friction (COF) generally decrease with the increase of temperature at different work rates. When the work rate was fixed at relatively high value (350mJ/s), the wear coefficient was found to decrease monotonically with temperature, while the COF experienced a peak at 200\ub0C. Analysis of the specimen fretted at 200\ub0C showed that the hard wear debris promoted abrasive wear and caused an increase in the COF. In addition, the formed oxide was thin, non-continuous and contained mainly cobalt monoxide (CoO), which contributed to the increase in the COF. Analysis of the specimen fretted at 550\ub0C showed that the wear damage decreased due to the formation of a continuous thick protective oxide containing mainly chromium (III) oxide (Cr<inf>2</inf>O<inf>3</inf>), known for its good tribological characteristics. It has also been observed that delamination wear took place within this oxide layer. When the oxide composition and thickness inside and outside the fretted area were compared, it was concluded that the real contact temperature exceeded 600\ub0C due to the frictional heat.Peer reviewed: YesNRC publication: Ye

Metformin attenuates streptozotocin-induced diabetic nephropathy in rats through modulation of oxidative stress genes expression.

Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion and/or action. One of the most important complications of this metabolic disease is diabetic nephropathy. Hyperglycemia promotes oxidative stress and hence generation of reactive oxygen species (ROS), which is known to play a crucial role in the pathogenesis of diabetic nephropathy. Recent studies have established that metformin, an oral hypoglycemic drug, possesses antioxidant effects. However, whether metformin can protect against diabetic nephropathy has not been reported before. The overall objectives of the present study are to elucidate the potential nephroprotective effect of metformin in a rat diabetic nephropathy model and explore the exact underlying mechanism(s) involved. The effect of metformin on the biochemical changes associated with hyperglycemia induced by streptozotocin was investigated in rat kidney tissues. In addition, energy nucleotides (AMP and ATP), and Acetyl-CoA in the kidney homogenates and mitochondria, and the mRNA expression of oxidative stress and pro-inflammatory mediators were assessed. Our results showed that treatment of normoglycemic rats with metformin caused significant increase in ATP, Acetyl-CoA, and CoA-SH contents in kidney homogenates and mitochondria along with profound decrease in AMP level. On the other hand, treatment of diabetic nephropathy rats with metformin normalized all biochemical changes and the energy status in kidney tissues. At the transcriptional levels, metformin treatment caused significant restoration in diabetic nephropathy-induced oxidative stress mRNA levels, particularly GSTα, NQO1, and CAT genes, whereas inhibited TNF-α and IL-6 pro-inflammatory genes. Our data lend further credence for the contribution of metformin in the nephroprotective effect in addition to its well known hypoglycemic actio