Therapeutic effects of gold nanoparticles synthesized using Musa paradisiaca peel extract against multiple antibiotic resistant Enterococcus faecalis biofilms and human lung cancer cells (A549).

Botanical-mediated synthesis of nanomaterials is currently emerging as a cheap and eco-friendly nanotechnology, since it does not involve the use of toxic chemicals. In the present study, we focused on the synthesis of gold nanoparticles using the aqueous peel extract of Musa paradisiaca (MPPE-AuNPs) following a facile and cheap fabrication process. The green synthesized MPPE-AuNPs were bio-physically characterized by UV-Vis spectroscopy, FTIR, XRD, TEM, Zeta potential analysis and EDX. MPPE-AuNPs were crystalline in nature, spherical to triangular in shape, with particle size ranging within 50 nm. The biofilm inhibition activity of MPPE-AuNPs was higher against multiple antibiotic resistant (MARS) Gram-positive Enterococcus faecalis. Light and confocal laser scanning microscopic observations evidenced that the MPPE-AuNPs effectively inhibited the biofilm of E. faecalis when tested at 100 µg mL-1. Cytotoxicity studies demonstrated that MPPE-AuNPs were effective in inhibiting the viability of human A549 lung cancer cells at higher concentrations of 100 µg mL-1. The morphological changes in the MPPE-AuNPs treated A549 lung cancer cells were visualized under phase-contrast microscopy. Furthermore, the ecotoxicity of MPPE-AuNPs on the freshwater micro crustacean Ceriodaphnia cornuta were evaluated. Notably, no mortality was recorded in MPPE-AuNPs treated C. cornuta at 250 µg mL-1. This study concludes that MPPE-AuNPs are non-toxic, eco-friendly and act as a multipurpose potential biomaterial for biomedical applications.

Effect of Copper Nanoparticles on the Flexural Strength of Heat Polymerized Acrylic Resin.

The aim of this study was to investigate the flexural strength of heat cure acrylic resin reinforced with varying concentration copper nanoparticles. The study followed ISO 20795-1-2013 guidelines for estimating the flexural strength. Hundred samples of heat cure acrylic resin of dimension were fabricated. The study had five groups and each group had 20 samples. The samples were grouped as per the concentration of copper (Cu) nanoparticles in acrylic. Three-point bending flexural strength was evaluated with universal testing machine. The load was directed at the midpoint of the sample at a cross-sectional speed of 5 mm/min. The fractured load was recorded and flexural strength was estimated. The data were statistically analyzed with analysis of variance and the post hoc test. The results displayed improved flexural strength in lower Cu concentrations. The increase in flexural strength was observed in 1% (78.38 MPa), 2% (73.08 MPa), and 3% (73.08 MPa) of Cu nanoparticles and it decreased beyond 3% increase in Cu nanoparticles. The tests were statistically insignificant (P <.05). The results concluded that the optimal concentration of Cu nanoparticles to be reinforced with heat cure PMMA is 1 gm. The flexural strength decreased with an increase in concentration of Cu nanoparticles.

Prosthodontic Rehabilitation of a Patient with Missing Teeth and Loss of Vertical Dimension Using Telescopic Overdentures.

Overdentures are one of the most sought-after treatment options for patients with few remaining natural teeth. They are desired as they tend to preserve the natural teeth and its intact periodontium. This helps in reducing the residual ridge resorption and preserve proprioception. These characteristics offer better masticatory ability in patients rehabilitated with overdentures when compared to conventional complete dentures. Enhancements such as telescopic denture for better retention prove to be efficient clinically. Telescopic dentures enable frictional type of retention. This is a case report of a partially edentulous patient with decreased vertical dimension, successfully rehabilitated with telescopic denture in relation to the maxilla and fixed partial prosthesis in the mandibular region.

In vivo 3D human vocal fold imaging with polarization sensitive optical coherence tomography and a MEMS scanning catheter.

We present in-vivo 3D human vocal fold images with polarization sensitive optical coherence tomography (PS-OCT). Characterizing the extent and location of vocal fold lesions provides useful information in guiding surgeons during phonomicrosurgery. Previous studies showed that PS-OCT imaging can distinguish vocal fold lesions from normal tissue, but these studies were limited to 2D cross-sectional imaging and were susceptible to sampling error. In-vivo 3D endoscopic imaging was performed by using a recently developed 2-axis MEMS scanning catheter and a spectral domain OCT (SD-OCT), running at 18.5 frames/s. Imaging was performed in the operating room with patients under general anesthesia and 3D images were acquired either by 2D scanning of the scanner on the sites of interest or by combining 1D scanning and manual sliding to capture whole length of the vocal fold. Vocal fold scar, polyps, nodules, papilloma and malignant lesions were imaged and characteristics of individual lesions were analyzed in terms of spatial distribution and variation of tissue structure and birefringence. The 3D large sectional PS-OCT imaging showed that the spatial extent of vocal fold lesions can be found non-invasively with good contrast from normal tissue.

Monitoring mouse retinal degeneration with high-resolution spectral-domain optical coherence tomography.

Progression of retinal degeneration in a mouse model was studied in vivo with high-resolution spectral-domain optical coherence tomography (SD-OCT). Imaging in 3D with high depth resolution (<3 mum), SD-OCT resolved all the major layers of the retina of control C57BL/6J mice. Images of transgenic mice having a null mutation of the rhodopsin gene revealed the anatomical consequences of retinal degeneration: thinning of the outer retina, including the outer plexiform layer (OPL), outer nuclear layer (ONL), and inner and outer segments (IS/OS). We monitored the progression of retinal degeneration in rd1 mice (C3H/HeJ) by periodically imaging the same mice from the time the pups opened their eyes on P13 to P34. SD-OCT images showed that the outer retina (OPL, ONL, IS/OS) had already thinned by 73% (100 to 27 mum) at eye opening. The retina continued to degenerate, and by P20 the outer retina was not resolvable. The thickness of entire retina decreased from 228 mum (control) to 152 mum on P13 and to 98 mum by P34, a 57% reduction with the complete loss in the outer retina. In summary, we show that SD-OCT can monitor the progression of retinal degeneration in transgenic mice.

Two-axis magnetically-driven MEMS scanning catheter for endoscopic high-speed optical coherence tomography.

A two-axis scanning catheter was developed for 3D endoscopic imaging with spectral domain optical coherence tomography (SD-OCT). The catheter incorporates a micro-mirror scanner implemented with microelectromechanical systems (MEMS) technology: the micro-mirror is mounted on a two-axis gimbal comprised of folded flexure hinges and is actuated by magnetic field. The scanner can run either statically in both axes or at the resonant frequency (>= 350Hz) for the fast axis. The assembled catheter has an outer diameter of 2.8 mm and a rigid part of 12 mm in length. Its scanning range is +/- 20 in optical angle in both axes with low voltages (1 approximately 3V), resulting in a scannable length of approximately 1 mm at the surface in both axes, even with the small catheter size. The catheter was incorporated with a multi-functional SD-OCT system for 3D endoscopic imaging. Both intensity and polarization-sensitive images could be acquired simultaneously at 18.5K axial scans/s. In vivo 3D images of human fingertips and oral cavity tissue are presented as a demonstration.

Release studies on niosomes containing fatty alcohols as bilayer stabilizers instead of cholesterol.

Monomers of some amphiphiles organize into bilayers to form liposomes and niosomes. Such bilayers are unstable or leaky and hence cholesterol is a common ingredient included to stabilize them. Cholesterol stabilizes bilayers, prevents leakiness, and retards permeation of solutes enclosed in the aqueous core of these vesicles. Other than cholesterol a material with good bilayer-stabilizing properties is yet to be identified. We have substituted cholesterol with fatty alcohols in niosomes containing polyglyceryl-3-di-isostearate (PGDS) and polysorbate-80 (PS-80) to explore their membrane-stabilizing property via permeation studies. Niosomes of polyglyceryl-3-di-isostearate, fatty alcohol/cholesterol, and polysorbate were prepared by ether injection method. Aqueous solution of ketorolac tromethamine (KT) was entrapped in them. The effects of alkyl chain length of fatty alcohols (C(12), C(14), C(16), C(18), and C(16+18)), of acyl chain length of polyoxyethylene sorbitan monoester surfactants, and of the molar ratio of lipid mixture on the release rate of ketorolac from niosomes were assessed by employing modified dissolution-dialysis method. Niosomes with cholesterol or fatty alcohols have exhibited a common release pattern. Niosomes containing fatty alcohol showed a considerably slower release rate of KT than those containing cholesterol. Based on the release rate, fatty alcohols can be ranked as stearyl

Experimental studies of transient, thermal depolarization in a Nd:glass laser rod.

Temporal studies of depolarization loss in a thermally strained, pulsed, Nd:glass laser system are reported. The probe beam consisted of a 70-mJ-20-ns, TEM(00), Nd:glass laser oscillator pulse. It was observed that, in all the cases of input pump energy density ø, the peak of the profile of depolarization loss is separated from the peak of population inversion by approximately 150 micros. The peak values of gain and depolarization loss showed a dependence of ø(5/3) and ø(2), respectively. Theoretical prediction of saturation of depolarization loss, at high input pump energy density, was found to be in agreement with the experimental observation.

Stability of Liquid Films Containing Monodisperse Colloidal Particles.

Thin liquid films containing colloidal particles are considered to be the key structural elements of three-phase foams containing liquid, gas, and colloidal particles. This study is aimed at understanding the stability of such films in the absence of any surfactants. The particles form a layered structure in the film and produce a stepwise thinning in the thin liquid films. We report here for the first time the effects of particle concentration and size on film thickness transition of curved liquid films containing monodispersed colloidal particles. The rate of stepwise film thinning was observed to be high when particle concentration was low and both particle size and film size were large. The phenomenon of stepwise film thinning (i.e., stratification) is rationalized on the basis of diffusion of colloidal particles from the film to the meniscus, i.e., the diffusive osmotic mechanism. There exists a critical film size below which at least one layer of particles always stays in the film (i.e., black spot expansion does not occur). This critical size is dependent upon both particle size and concentration. Also, Monte Carlo simulations of the film show that, at a high particle concentration, better particle in-layer structure develops that increases the energy barrier, inhibiting particle diffusion from the film to the bulk meniscus. Copyright 2001 Academic Press.