An improved dental composite with potent antibacterial function

A new BisGMA-based antibacterial dental composite has been formulated and evaluated. Compressive strength and bacterial viability were utilized to evaluate the formed composites. It was found that the new composite exhibited a significantly enhanced antibacterial function along with improved mechanical and physical properties. The bromine-containing derivative-modified composite was more potent in antibacterial activity than the chlorine-containing composite. The modified composites also exhibited an increase of 30–53% in compressive yield strength, 15–30% in compressive modulus, 15–33% in diametral tensile strength and 6–20% in flexural strength, and a decrease of 57–76% in bacterial viability, 23–37% in water sorption, 8–15% in shrinkage, 8–13% in compressive strength, and similar degree of conversion, than unmodified composite. It appears that this experimental composite may possibly be introduced to dental clinics as an attractive dental restorative due to its improved properties as well as enhanced antibacterial function

Extraordinary Optical Transmission in Aligned Carbon Nanotube Devices at Terahertz Frequencies.

In the phenomenon known as extraordinary optical transmission (EOT), a narrow band of selected frequencies are transmitted when incident on an array of subwavelength periodic apertures where the resonant frequency is determined by the geometry of the array of apertures and optical properties of the metal-dielectric interface. This takes place due to the excitation of surface plasmon polaritons (SPPs) at the metal and dielectric interface. Using the COMSOL Multiphysics software RF Module, a unit cell of a carbon nanotube (CNT) based EOT device is modeled in order to verify theoretical calculations of the resonant frequency using S-parameter calculations. The simulation of the interaction of the THz light with the CNT EOT device exhibits a resonant transmission at 235 GHz. Further, the transmission falls exponentially with increasing device thickness of the device, and the transmission peak reaches its maximum value at the skin depth. Although some of the transmission features, such as Wood’s anomalies, are seen in the modeled device only, the other numerical results show good agreement with the experimental observations reported in literature. The fabricated single-walled carbon nanotube devices with 100 nm thickness do not indicate any resonances; however any such resonances might be weak due to the thin nature of the samples