Evaluation of Helium Plasma Surface Modification on Tensile Bond Strength of Denture Base Materials: A Scanning Electron Microscope Study

The purpose of this study was to compare the effect of helium plasma treatment on tensile bond strength between polymethylmethacrylate and soft liner material. For the tensile test, acrylic samples (30 x 10 x 10 mm³; n=100) were prepared. Acrylic samples were divided into five surface groups (n = 10/group) and treated by different concentrations of helium plasma: G I: Control group (untreated), G II: 100% Helium plasma-treated group, G III: 90% Helium plasma-treated group, G IV: 85% Helium plasma-treated group, G V: 80% Helium plasma-treated group. After plasma treatment, the soft liner was processed between two acrylic resin blocks according to the manufacturer's instructions and polymerized. The surface properties were evaluated by scanning electron microscopy and atomic force microscopy. All samples were submitted to a tensile test using a universal testing machine. After failure, the surface properties were evaluated by stereomicroscope. One-way analysis of variance was used to compare the groups. p <0.05 value was considered statistically significant. While the highest mean tensile bond strength value was obtained with the G III (1.56 ± 0.13 MPa), the lowest value was observed with the G I (0.95 ± 0.2 MPa). In addition, it was observed that the surface roughness increased the most in G III.

Second Harmonic Generation of Femtosecond Laser Pulses of Central Wavelength 1000 nm, 1100 nm and 1300 nm Using ZnO Nanorods

In this work high density ZnO nanorods were grown on glass substrate by using a two steps method. In the first step drop-casting method was used for growth of seed layer by taking Zinc Acetate Dihydrate as precursor. In the second step, ZnO nanorods were prepared through Chemical Bath Deposition process on this seed layer by taking Zinc Nitrate as precursor. Field Emission Scanning Electron Microscope study was done to study the morphology of grown ZnO nanorods. From this study the average diameter and length of nanorods were found to be 33 nm and 270 nm respectively. These nanorods are successfully used for second harmonic generation (SHG) of femtosecond laser pulses of central wavelengths like 1000 nm, 1100 nm and 1300 nm. Discussion is given on the significance of this result along with its potential application.

Influence of High-Concentration LLDPE on the Manufacturing Process and Morphology of Pitch/LLDPE Fibres

A high modulus of elasticity is a distinctive feature of carbon fibres produced from mesophase pitch. In this work, we expand our previous study of pitch/linear low-density polyethylene blend fibres, increasing the concentration of the linear low-density polyethylene in the blend into the range of from 30 to 90 wt%. A scanning electron microscope study showed two distinct phases in the fibres: one linear low-density polyethylene, and the other pitch fibre. Unique morphologies of the blend were observed. They ranged from continuous microfibres of pitch embedded in linear low-density polyethylene (occurring at high concentrations of pitch) to a discontinuous region showing the presence of spherical pitch nodules (at high concentrations of linear low-density polyethylene). The corresponding mechanical properties—such as tensile strength, tensile modulus, and strain at failure—of different concentrations of linear low-density polyethylene in the pitch fibre were measured and are reported here. Thermogravimetric analysis was used to investigate how the increased linear low-density polyethylene content affected the thermal stability of linear low-density polyethylene/pitch fibres. It is shown that selecting appropriate linear low-density polyethylene concentrations is required, depending on the requirement of thermal stability and mechanical properties of the fibres. Our study offers new and useful guidance to the scientific community to help select the appropriate combinations of linear low-density polyethylene/pitch blend concentrations based on the required mechanical property and thermal stability of the fibres.

A Comparative Evaluation of Smear Layer Removal Using Erbium:YAG Laser-Activated Irrigation, Sonic Irrigation, and Manual Dynamic Irrigation: A Scanning Electron Microscope Study

Introduction: The conventional chemomechanical procedures are ineffective in complete disinfection of the pulp space due to the complexities of the root canal architecture. The present study aims to compare the efficacy of erbium: YAG laser-activated irrigation, sonic irrigation, and manual dynamic irrigation in the removal of the smear layer through a scanning electron microscope study. Methods: Fifty extracted single rooted mandibular premolars with single canal were used and instrumented until F3 ProTaper rotary file reached the working length. Upon the completion of the canal preparation, each specimen was irrigated with 3 mL of 4% NaOCl for 3 minutes, 3 mL saline for 1 minute and 3 mL of 17% EDTA for 3 minutes. The teeth were assigned to three experimental groups (n=15 each): manual dynamic irrigation, sonic irrigation (EndoActivator), and Er:YAG laser using an X pulse tip. Root canals were sectioned longitudinally and the smear layer at the apical, middle and coronal third was examined under a scanning electron microscope. Smear layer scores were analyzed by Kruskal-Wallis and Mann-Whitney U tests at P=0.05. Results: The Er:YAG laser group showed significantly lower smear layer scores in the apical third as compared to all other groups. EndoActivator resulted in better cleaning efficacy at the apical area compared to manual dynamic agitation. Conclusion: This study showed results in favor of Er:YAG with an X-pulse tip followed by EndoActivator activation.

Surface ultrastructure of the adult and juvenile stages of the trematode Astiotrema impletum (Looss, 1899) Looss 1900 (incertae sedis) from the Nile puffer, Tetraodon lineatus Linnaeus, 1758

Summary A scanning electron microscope study was performed on the surface of the trematode Astiotrema impletum (Looss, 1899) Looss 1900 from the Nile puffer, Tetraodon lineatus Linnaeus, 1758 (Syn. Tetraodon fahaka) for the first time. Adult A. impletum have a markedly large, sub-terminal oral sucker and a small ventral sucker. As with most trematodes, tegumental spines are concentrated anteriorly and are absent just anterior the ventral sucker. Spines have serrated tips on a short, tongue–shaped body. At the level of the ventral sucker the base of each spine exhibits a three bulbous-like structure that can be partially or completely withdrawn into the tegument. Sensory papillae are concentrated around the oral and ventral suckers and genital pores. Papillae are conical or knob-like, either ciliated or non-ciliated; some are protruded and others are embedded inside the tegument. In the juvenile stage, spines are smaller, less well-developed and tightly packed. The cytoplasmic processes of the posterior quarter of body show brain-like velvety appearance on the adult and small cobblestone-like on the juvenile.

Bio efficacy of Cinnamaldehyde from Cinnamomum verum essential oil against Culex quinquefasciatus (Diptera: Culicidae)

This research aims to study the efficacy of Cinnamomum verum (Cv) extracts for ovicidal, larvicidal, and repellent activities against Culex quinquefasciatus mosquito vectors. The active components of C. verum or cinnamon oil by Gas Chromatography (GC) analysis showed the highest cinnamaldehyde at 83.53%. For ovicidal assay, C. verum essential oil at concentrations 12.5, 25 and 50 ppm at 72 h had 100% egg hatch inhibition and had a significant difference when compared to the control group (p<0.05). Larvicidal activity showed that concentrations of 25 and 50 ppm were highly effective in killing 100% mosquito larvae. Morphological changes in egg raft showed a faded color and eggs that seemed to have split from their raft while the larvae changed to a pale white wrinkled body with a destroyed inner tube of the body and were motionless. A Scanning electron microscope study showed that the eggshell and micropyle were wrinkled with the chitin peeled out. After treatment with cinnamon oil, larvae appeared to have a wrinkled body, the thorax and abdominal cuticle were also destroyed with high density of oil particles observed on mouth brushes and obstructing the spiracle. The repellent assay showed that cinnamon oil could repel both male and female mosquitos for up to 180 min. From the results, it was concluded that cinnamon oil had highly effective repellency against Culex quinquefasciatus adults and insecticidal activity on eggs and larvae stages evidenced by LC50 at 6.59±0.54, 9.07±0.67 and 36.91±7.56 ppm and its morphological changes indicated how the mosquito could not survive after cinnamon oil treatment hence this may be a useful alternative method that is green friendly for controlling mosquitoes in endemic areas.