Correlation between pixel value of CBCT and Hounsfield Unit of MDCT on teeth and mandible cortical bone

Cone-beam computed tomography (CBCT) is an imaging modality widely used in dentistry over multi detector computed tomography (MDCT). It is in view of its high resolution with relatively lower dose. MDCT is able to show Hounsfield Unit (HU) which is proportional to x-ray attenuation degree by the tissue. The x-ray attenuation degree in CBCT is shown in grayscale value with pixel values unit. The aim of this study was to determine the correlation of pixel values in CBCT with HU in MDCT. We used secondary data from RSGM Universitas Padjajaran patient who had CBCT and MDCT. Measurement was done on the cortical areas (lingual, buccal, and posterior side) of the mandible and teeth 47 (email, dentin, and pulp) with 5 regions of interest (ROIs) on each area. DICOM software was used for the measurement on CBCT and MDCT data. The result indicated a strong correlation between pixel value in CBCT and HU in MDCT on the cortical bone and teeth area (R=0.846). Linear regression resulted in an equation to derive HU value from pixel value of cortical bone and teeth area, which is y = 1,9011x + 177,15. The conclusion is HU can be derived from CBCT by converting with regression equation

Gateway state-mediated, long-range tunnelling in molecular wires

If the factors controlling the decay in single-molecule electrical conductance G with molecular length L could be understood and controlled, then this would be a significant step forward in the design of high-conductance molecular wires. For a wide variety of molecules conducting by phase coherent tunneling, conductance G decays with length following the relationship G = Aexp-\b{\eta}L. It is widely accepted that the attenuation coefficient \b{\eta} is determined by the position of the Fermi energy of the electrodes relative to the energy of frontier orbitals of the molecular bridge, whereas the terminal anchor groups which bind to the molecule to the electrodes contribute to the pre-exponential factor A. We examine this premise for several series of molecules which contain a central conjugated moiety (phenyl, viologen or {\alpha}-terthiophene) connected on either side to alkane chains of varying length, with each end terminated by thiol or thiomethyl anchor groups. In contrast with this expectation, we demonstrate both experimentally and theoretically that additional electronic states located on thiol anchor groups can significantly decrease the value of \b{eta}, by giving rise to resonances close to EF through coupling to the bridge moiety. This interplay between the gateway states and their coupling to a central conjugated moiety in the molecular bridges creates a new design strategy for realising higher-transmission molecular wires by taking advantage of the electrode-molecule interface properties