Vickers

Background This study aimed to evaluate and compare the abrasive and erosive wear resistance of Cention N and titanium dioxide (TiO2 ) nanoparticle-enriched Cention N after three years of brushing simulation. Methodology A total of 48 freshly extracted mandibular molars were mounted in acrylic blocks and divided into two groups of 24 molars based on the type of restorative material used to restore them. Cavities of a standardized size were prepared. Group A was restored with Cention N, and group B was restored with 5% TiO2 -enriched Cention N...

Advancements in cochlear implants (CIs) have led to a significant increase in bilateral CI users, especially among children. Yet, most bilateral CI users do not fully achieve the intended binaural benefit due to potential limitations in signal processing and/or surgical implant positioning. One crucial auditory cue that normal hearing (NH) listeners can benefit from is the interaural time difference (ITD), i.e ., the time difference between the arrival of a sound at two ears. The ITD sensitivity is thought to be heavily relying on the effective utilization of temporal fine structure (very rapid oscillations in sound)...

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Materials from green resources boast a low carbon footprint, forming the foundation of the circular economy approach in materials science. Thus, in this study, waste poly(ethylene terephthalate) (PET) was subjected to depolymerization using propylene glycol (PG), and subsequent polycondensation with bio-based maleic anhydride (MA) produced unsaturated polyester resin (b-UPR). Bio-derived acryloyl-modified Kraft lignin (Kf L-A) served as a vinyl reactive filler in the b-UPR matrix to create b-UPR/Kf L-A composites...

This work has studied the co-addition of Sc and Zr elements into the Al-1.75wt%Fe-1.25wt%Ni eutectic alloy. The changes in the microstructure, electrical conductivity, and Vickers hardness of the Al-1.75wt%Fe-1.25wt%Ni-0.2wt%Sc-0.2wt%Zr alloy during heat treatment were studied. The results showed that two-step aging can effectively improve the aging response of the alloy over the single-step aging method. This was ascribed to the minimization of the diffusion difference between Sc and Zr elements. Furthermore, the homogenization treatment can also improve the aging response of the alloy by alleviating the uneven distribution of Sc and Zr...

Oxide Dispersion Strengthened (ODS) ferritic steels are promising materials for the nuclear power sector. This paper presents the results of a study on the sintering process using the Spark Plasma Sintering (SPS) technique, focusing on ODS ferritic steel powders with different contents (0.3 and 0.6 vol.%) of Y2 O3 . The novelty lies in the analysis of the effect of pre-annealing treatment on powders previously prepared by mechanical alloying on the microstructure, mechanical, and thermal properties of the sinters...

We report a new nanoporous amorphous carbon (NAC) structure that achieves both ultrahigh strength and high electrical conductivity, which are usually incompatible in porous materials. By using modified spark plasma sintering, we create three amorphous carbon phases with different atomic bonding configurations. The composite consists of an amorphous sp2-carbon matrix mixed with amorphous sp3-carbon and amorphous graphitic motif. NAC structure has isotropic electrical conductivity of up to 12,000 S/m, a Young's modulus of up to ∼5 GPa, and Vickers hardness of over 900 MPa...

This study aimed to evaluate and compare the impact of additives such as ZrO2 and SiO2 nanoparticles (ZrO2 NP or SiO2 NP) on the hardness, surface roughness, and color stability of 3D printed provisional restorations. Two hundred samples in total were printed using 3D printed resins (ASIGA, and NextDent). Each resin was modified with ZrO2 NPs or SiO2 NPs in two different concentrations (0.5 wt% and 1 wt%), while one group was kept unmodified (n = 10). Disc-shaped (15 × 2.5 mm) samples were designed and printed in accordance with the manufacturer's recommendation...

OBJECTIVES: A tricalcium silicate-based cement, Biodentine™, has displayed antibiofilm activity when mixed with chitosan powder. This study aimed to assess the effect of chitosan incorporation on the physico-mechanical and biological properties of Biodentine™. METHODS: In this study, medium molecular weight chitosan powder was incorporated into Biodentine™ in varying proportions (2.5 wt%, 5 wt%, 10 wt%, and 20 wt%). The setting time was determined using a Vicat apparatus, solubility was assessed by calculating weight variation after water immersion, radiopacity was evaluated and expressed in millimeters of aluminum, the compressive strength was evaluated using an Instron testing machine, and the microhardness was measured with a Vickers microhardness tester...

This study investigates the viscoelastic deformation mechanisms of bone as a response to Vickers hardness indentation. We utilized advanced high-resolution scanning electron microscopy (SEM) to investigate a distinct deformation pattern that originates from the indentation site within the bone matrix. The focus of our research was to analyze a unique deformation mechanism observed in bone tissue, which has been colloquially termed as "screw-like" due to its resemblance to a screw thread when viewed under an optical microscope...

OBJECTIVE: Acupuncture, acknowledged as a potent non-pharmacological therapy, is frequently employed to alleviate pain. Despite its widespread use, there has been a lack of overarching bibliometric analysis of clinical research on acupuncture analgesia. We aimed to summarize current patterns, hotspots, and development trends in this field through bibliometric analysis. METHODS: This study evaluates academic publications retrieved from the Web of Science database (2010...

OBJECTIVES: This study aimed to compare the physical and mechanical properties of four denture base materials: Polyan IC (PA), milled polymethylmethacrylate (PMMA), three-dimensional (3D)-printed resin (3DP), and SR Ivocap (SR). METHODS: Ninety-six samples were prepared and divided into four groups as follows. Group A consisted of 3DP (Asiga DentaBASE, Asiga) fabricated using a manufacturer-recommended 3D printer (Asiga Pro 4k, Asiga). Group B comprised milled PMMA (MP) (Ivotion Base, Ivoclar Vivadent)...

BACKGROUND: Despite several interventions demonstrating benefit to people living with dementia and their caregivers, few have been translated and implemented in routine clinical practice. There is limited evidence of the barriers and facilitators for commissioning and implementing health and social care interventions for people living with dementia. The aim of the current study was to explore the barriers and facilitators to commissioning and implementing health and social care interventions for people with dementia, using a dementia friendly exercise and physical activity-based intervention (PrAISED [Promoting Activity, Stability and Independence in Early Dementia and Mild Cognitive Impairment]) as a case study...

PURPOSE: Dental ceramics deteriorate as a result of thermal aging and exposure to acidic solutions, which change their microhardness and surface roughness. This study assessed the resistance of several computer-aided design and computer-aided manufacturing (CAD-CAM) restorative dental materials in terms of surface roughness and microhardness following exposure to acidic solutions and thermal aging. MATERIALS AND METHODS: Five different monolithic CAD-CAM restorative materials, two leucite-reinforced glass ceramics (G-Ceram and CEREC Blocs), a zirconia-infiltrated lithium silicate (Celtra Duo), a resin nanoceramic (Grandio), and monolithic zirconia (inCoris TZI), were used to create 2-mm-thick rectangular specimens (n = 100)...

We found evidence that Army cadets improved their gaze behavior and performance across time under high and low pressure in a shooting task. The purpose of the study was to determine if male and female cadets developed an optimal quiet eye (QE) onset, a longer QE duration, and decreased pupil diameter variability (PDV) over time under low (LP) and high pressure (HP) conditions. The study was carried out over four sessions, with intervals of 4.5 months. During each session, 16 men and 12 women, first-year cadets of The Brazilian Army Academy, performed ten pistol shots under counterbalanced LP and HP conditions...

OBJECTIVE: The aim of this in vitro study was to evaluate the effect of radiotherapy on the surface microhardness and roughness of different bioactive restorative materials. MATERIALS AND METHODS: A total of 60-disc specimens (5 mm × 2 mm) were performed in four groups (n = 15 each) from Equia Forte HT, Cention N, Activa Bioactive Restorative, and Beautifil II. Following the polishing procedure (600, 1000, 1200 grit silicon carbide papers), all specimens were irradiated at 2 Gy per fraction, five times a week for a total dose of 70 Gy in 30 fractions over 7 weeks...

BACKGROUND AND AIM: Teeth bleaching, although considered safe and conservative, cause microscopic changes in the tooth structure. The aim of this study is to evaluate the bleaching efficacy of carbamide peroxide (CP) bleaching gel when modified with the incorporation of bioactive glass (BG) and hydroxyapatite (HA) and its effect on enamel microhardness. MATERIALS AND METHODS: Forty-five maxillary incisors were decoronated, artificially stained and mounted in acrylic...

Assessment of contemporary canal medicaments (Triple antibiotic paste (TAP), Bio-C Temp, and Nano silver gel activated by visible blue light on the dentin microhardness (MH) and push-out bond strength (PBS) of AH plus endodontic sealer METHOD: : Sixty extracted premolars were obtained and decontaminated. Canal cleaning and shaping were performed. The samples were randomly allocated into four groups based on the intracanal medicaments. Group 1= CH paste, Group 2= TAP, Group 3= Bio-C Temp, and Group 4= Nano-silver gel activated by visible blue light...

Eculizumab, a monoclonal antibody against complement C5, is a novel therapy to treat refractory myasthenia gravis (MG). The present review was undertaken to study the role of eculizumab in MG. This includes the drug's mechanism, pharmacokinetics, clinical trial findings, tolerability, side effects, safety, dosage, administration, and cost. An English-language search for relevant items was undertaken using Embase and PubMed from 1946 to present. Clinical trial registries/databases and websites were also searched for relevant data...

BACKGROUND: Dementia prevalence is predicted to triple to 152 million globally by 2050. Alzheimer's disease (AD) constitutes 70% of cases. There is an urgent need to identify individuals with preclinical AD, a 10-20-year period of progressive brain pathology without noticeable cognitive symptoms, for targeted risk reduction. Current tests of AD pathology are either too invasive, specialised or expensive for population-level assessments. Cognitive tests are normal in preclinical AD...