Novel microbial synthesis of titania nanoparticles using probiotic Bacillus coagulans and its role in enhancing the microhardness of glass ionomer restorative materials.

Dental caries is a commonly occurring non-communicable disease throughout the world that might compromise the quality of any individual's life. Glass ionomer cements (GIC) are the most acceptable restorative materials due to their ease of manipulation, minimal tooth loss and least invasive strategy; however, they lack mechanical stability that has become a point of concern. Nanoparticles (NPs) are an outstanding option for modifying and enhancing the properties of dental materials. The focus of this study was to prepare novel, biocompatible titania dioxide (TiO2) NPs as a dental-restorative material using an efficient probiotic Bacillus coagulans. The prepared NPs were incorporated into glass ionomer restorative material at varying concentrations and investigated for cell viability percentage, microhardness and surface morphology. Results indicated that pure 100% anatase phase TiO2 NPs with particle size of 21.84 nm arranged in smooth, spherical agglomerates and clusters forms. These NPs depicted cell viability > 90%, thus confirming their non-cytotoxic behavior. GIC restorative materials reinforced by 5% titania (TiO2) NPs demonstrated the highest microhardness in comparison to the control group and other experimental groups of the study. Surface morphology analysis revealed a reduction in cracks in this novel dental-restorative material supporting its compatible biological nature with better hardness strength and negligible crack propagation. Overall, these results indicated that TiO2 NPs produced using a biological approach could be easily used as restorative materials in dental applications.

Synthesis of TiO2 nanoparticles and demonstration of their antagonistic properties against selected dental caries promoting bacteria.

Objective: To evaluate antagonistic role of titanium oxide nanoparticles against selected dental caries promoting bacteria. Methods: This in vitro-experimental study was conducted at Pakistan Institute of Engineering and Applied Sciences (PIEAS), National Institute of Health (NIH) and School of Dentistry (SOD), Islamabad for the period of one year from February 2022 to January 2023. Modified hydrothermal heating method was used to prepare titanium oxide nanoparticles (TiO2Nps). Size, shape, phase, band gap energy, surface and elemental composition of Nps were deciphered by application of various modern techniques including x-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), UV-Vis diffuse reflectance spectroscopy (DRS), atomic force microscopy (AFM), energy dispersive x-ray spectroscopy (EDX). Antimicrobial action of nanoparticles was evaluated against representatives of gram-positive (mono-derm) and Gram negative bacteria (di-derm) responsible for promoting dental caries. The zones of inhibition were calculated by disc diffusion method for each bacterial strain. Results: Characterization revealed that TiO2Nps were having an average size of 54nm, showing anatase-rutile phase having spherical, with very few- irregularly shaped particles. TiO2Nps contained only pure titanium and oxygen in the EDX image but organic compounds in FTIR scan. Results of antimicrobial action indicated their potent bactericidal action against Pseudomonas aeruginosa (20mm), Escherichia coli (19mm) and Lactobacillus acidophilus (19nm) while comparatively less activity against Staphylococcus aureus (16mm).. Conclusion: TiO2Nps fabricated by modified protocol displayed an effective antimicrobial activity and can be used as an alternative to the contemporary chemotherapeutics against selected bacterial pathogens to prevent dental caries.

Synthesis and Characterization of Titanium Oxide Nanoparticles with a Novel Biogenic Process for Dental Application.

The prevalence of dental caries has been largely consonant over time despite the enhancement in dental technologies. This study aims to produce novel GIC restorative material by incorporating TiO2 nanoparticles synthesized by Bacillus subtilis for the treatment of dental caries. The TiO2 nanoparticles were prepared by inoculating a fresh culture of Bacillus subtilis into a nutrient broth for 24 h, which was then characterized by XRD, DRS, FTIR, AFM, SEM, TEM and EDX. These TiO2 nanoparticles were incorporated in GIC restorative material at different concentrations (0-10% TiO2 -GIC) and were tested for their mechanical properties in a universal testing machine. The XRD analysis revealed synthesis of anatase and rutile-phased TiO2 nanoparticles with a particle size of 70.17 nm that was further confirmed by SEM and TEM analysis. The EDX spectrum indicated prominent peaks of titanium and oxygen with no impurities in the prepared material. Treatment with 5% TiO2 -GIC proved to be most effective for the treatment of dental caries with no observable cytotoxic effect. An increase in the compressive strength of TiO2 nanoparticle-reinforced GIC was observed as the concentration of the TiO2 nanoparticles was increased up to 5%; subsequently, the compressive strength was lowered. An increase in the flexural strength was observed in GIC containing 0%, 3% and 5% TiO2 nanoparticles sequentially. Based on the results, it can be concluded that Bacillus subtilis-derived TiO2 nanoparticles have excellent potential for developing next generation of restorative materials for dental issues.

Pt-Ni@PC900 Hybrid Derived from Layered-Structure Cd-MOF for Fuel Cell ORR Activity.

Fuel cell technology is the supreme alternate option for the replacement of fossil fuel in the current era. Pt alloys can perform well as fuel cell electrodes for being used as catalytic materials to perform the very notorious oxygen reduction reaction. In this regard, first, a layered metal-organic framework with empirical formula [C8H10CdO7] n ·4H2O is synthesized and characterized using various experimental and theoretical techniques. Then, a nanostructured porous carbon material with a sheet morphology (PC900) having a high BET surface area of 877 m2 g-1 is fabricated by an inert-atmosphere thermal treatment of the framework upon heating up to 900 °C. Pt and Ni nanoparticles are embedded into PC900 to prepare a homogenized hybrid functional material, i.e., Pt-Ni@PC900. The Pt-Ni@PC900 hybrid is proved to be an excellent ORR catalyst in terms of half-wave potential and limiting current density with 7% Pt loading compared with the commercially available 20% Pt/C catalyst. Pt-Ni@PC900 also shows stability of current up to 12 h with only a very small variation in current. This work highlights the importance of Pt alloys in future large-scale commercial applications of fuel cells.

Risk Factor for Cardiac Permanent Pacemaker Infection.

BACKGROUND: Cardiac pacemaker infections have increased globally due to increase in demand and lack of adequate knowledge about its significantly contributing risk factors. This study was therefore aimed to determine the prevailing causative microbes and risk factors of both single and dual chamber permanent pacemaker infections. METHODS: This was a retrospective case control study. Cases were selected as culture positive swab, Temporary pacemaker wire or catheter were matched with three controls for each variable using chi square test. Multivariate regression analysis was done to determine risk factors. RESULTS: Among 47 cases, 23.4% cases were infected by methicillin resistant staph aureus, 14.9% by methicilin susceptible Staphylococcus aureus, 10.6% by pseudomonas, 8.5% by escherichia coli and 6.4% by klebsiella. Temporary pacemaker/Central line placed >24 hours ago before permanent pacemaker implantation, remnant pacemaker leads, corticosteroid use, no antibiotic prophylaxis, diabetes, smoking and non-absorbable stitches had statistically significant association with permanent pacemaker infection using multivariate regression model analysis. Chronic obstructive pulmonary disease and non-absorbable stitches had a non-significant association. CONCLUSIONS: Temporary pacemaker/Central line placed >24hours before permanent pacemaker implantation, remnant pacemaker leads, corticosteroid use, no antibiotic prophylaxis, diabetes, smoking and use of non-absorbable stitches are risk factors for permanent pacemaker infection. Staph aureus is the most prevalent microorganism causing infection.

Two-dimensional transition metal carbide (Ti3C2Tx) as an efficient adsorbent to remove cesium (Cs+).

Industrial utilization of nuclear resources greatly depends on the effective treatment of nuclear waste. The efficient removal of radioactive nuclides from liquid effluents by using different adsorbents has thus become crucial. Herein, for the first time, two-dimensional transition metal carbides (MXenes) are investigated as scavengers of cesium (Cs+) from contaminated water. Due to the combined advantages of the layered structure and the presence of heterogeneous sites (hydroxyl, oxygen and fluorine groups), the adsorbent reached the steady state within 1 min with the maximum Cs+ adsorption capacity of 25.4 mg g-1 at room temperature. The kinetics studies of the Cs+ scavenging process demonstrated that the adsorption of Cs+ followed the pseudo-second-order model whereas the adsorption equilibrium data obeyed the Freundlich model. Thermodynamic studies revealed that the adsorption process was endothermic. The adsorbent showed an excellent Cs+ removal efficiency in neutral to slightly alkaline solutions. Moreover, it can retain Cs+ even in the presence of a high concentration of competing cations (Li+, Na+, K+, Mg2+ and Sr2+). The Cs+ loaded adsorbent was regenerated with a 0.2 M HCl solution and reused at least five times for over 91% removal of contaminants.

Characterization of the interactions between coumarin-derivatives and acetylcholinesterase: Examination by NMR and docking simulations.

Alzheimer's disease (AD) is one of the most common forms of dementia and a significant threat to the elderly populations, especially in the Western world. The rapid hydrolysis of the principal neurotransmitter into choline and acetate by acetylcholinesterase (AChE) at synapses causes the loss of cognitive response that becomes the real cause of AD. Therefore, inhibition of AChE is the most fundamental therapy among currently available treatments for AD. In this context, we designed and performed molecular recognitions studies of coumarin-based inhibitors towards AChE. STD NMR and Tr-NOESY applications were utilized to evaluate the binding epitope, the dissociation constant (KD) and bound conformations of these inhibitors within this inhibitor-AChE complex. Compound 1, which has a similar inhibition activity to tacrine (a current drug) led in this study as a stronger binder with KD = 30 µM ,even greater than tacrine (KD = 140 µM). Moreover, docking simulations mimic NMR results and provided evidence of synchronizing binding of compound 1 with three sites; the peripheral anionic site, the bottom of the gorge, and the catalytic site. Therefore, we envisioned from our experimental and theoretical results that coumarin-based inhibitors containing a piperidinyl scaffold might be a potential drug candidates for AD in the future.

Nanostructured multilayer TiO2-Ge films with quantum confinement effects for photovoltaic applications.

Multilayer TiO(2)-Ge thin films have been deposited using electron beam evaporation and resistive heating. The thickness of the TiO(2) layers is 20 nm, while the thickness of the Ge layers varies from 2 to 20 nm with a step of 2 nm away from the substrate. These films were characterized by studying their optical, electrical, and structural properties. The films were annealed at various temperatures up to 500 degrees C for 2 h. The films are amorphous up to an annealing temperature of 400 degrees C, although Raman spectra suggest short-range ordering (and adjustments). The films annealed at 450 and 500 degrees C exhibit X-ray reflections of Ge and anatase TiO(2). Illumination in sunlight increases the conductivity of the as-deposited and annealed films. The band gap of the amorphous films changes from 1.27 to 1.41 eV up to 400 degrees C; the major contribution is possibly through direct transition. Two band gap regimes are clearly seen after 450 and 500 degrees C, which have been assigned to an indirect band gap at about 1.2 eV and a direct band gap at about 1.8 eV. Conductivity of the multilayer films has been higher than that of pure Ge film. The conductivity increases with annealing temperature with abrupt increase at about 380 degrees C. The results imply that the TiO(2)-Ge multilayer films may be employed as heterojunctions with tunable band gap energy as related to quantum confinement effects.

Superparamagnetic bimetallic iron-palladium nanoalloy: synthesis and characterization.

Iron-palladium nanoalloy in the particle size range of 15-30 nm is synthesized by the relatively low temperature thermal decomposition of coprecipitated [Fe(Bipy)(3)]Cl(2) and [Pd(Bipy)(3)]Cl(2) in an inert ambient of dry argon gas. The silvery black Fe-Pd alloy nanoparticles are air-stable and have been characterized by EDX-RF, XRD, AFM, TEM, magnetometry, (57)Fe Mössbauer and impedance spectroscopy. This Fe-Pd nanoalloy is in single phase and contains iron sites having up to 11 nearest-neighboring atoms. It is superparamagnetic in nature with high magnetic susceptibility, low coercivity and hyperfine field.