Effect of voxel size on the accuracy of 3D reconstructions with cone beam CT.

OBJECTIVES: The various types of cone beam CT (CBCT) differ in several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data. METHODS: The study sample comprised 70 teeth (from the Institut d\u27Anatomie Normale, Strasbourg, France). The teeth were scanned with a KODAK 9500 3D® CBCT (Carestream Health, Inc., Marne-la-Vallée, France), which has two voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the KODAK 9000 3D® CBCT (Carestream Health, Inc.) (CBCT 76 µm group) and the SCANCO Medical micro-CT XtremeCT (SCANCO Medical, Brüttisellen, Switzerland) (micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA® software (Visualization Sciences Group, Burlington, MA), tooth volumetric measurements were obtained. RESULTS: The Bland-Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing-Bablok method). CONCLUSIONS: CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed

Why Bananas Matter: An introduction to the history of banana domestication

researc

An interview with Luc de Heusch

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The prohormone processing activity is enriched in a low-density subpopulation of chromaffin granules

AbstractBovine adrenomedullary chromaffin granules can be separated into two subpopulations by differential centrifugation. The subpopulation which sediments at the interface of two sucrose layers, 1.6 and 1.8 M respectively, is found to be enriched about 10-times in prohormone processing activity, as measured by in vitro degradation of synthetic peptide substrates. The enhanced proteolytic activity is not due to lysosomal contaminations which are very low and only slightly increased in the more active fraction. The low density of the enriched subpopulation suggests that we are dealing with immature granules. The physiological implications of this finding are discussed. Furthermore, the enriched fraction can be used as the starting material for the isolation ofproenkephalin processing enzymes

Very High Data Rate Optical Wireless Communication with Micro Organic LED

International audienceWe present a broadband free space light communication using high-speed micro organic light emitting diode (OLED) as transmitter. We report first the design and bandwidth measurements of innovative OLEDs whose size are in the range of tens of micrometres. For OLEDs with reduced active area such as 40 µm x 40 µm, a cut-off frequency up to 345 MHz is reached. Then a free-space optical wireless link is build based on these high-speed micro-OLED. Using Direct Current Optical-Orthogonal Frequency Division Multiplexing) with adaptive bit and energy loading, we achieve a data rate of 2.85 Gb/s

Structure of a LIFI dedicated binary pixel array

International audienceIn recent years, visible light communication (VLC) have attracted a lot of attention as the key component of LIFI networks. Alongside complex and cumbersome mono LED implementations, which are used in labs to achieve extremely high data rate transmissions, slower but much more compactmatrix emitters are found in the literature. In this paper, we discuss the choice of matrix architecture for data distribution and transmitter operation scheme

Yes, there were bananas in Cameroon more than 2000 years ago

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Why Bananas Matter: An introduction to the history of banana domestication

info:eu-repo/semantics/publishe

2.85-Gb/s Organic Light Communication With a 459-MHz Micro-OLED

We present a broadband free space light communication system using high-speed organic light emitting diodes (OLEDs) as transmitters. Firstly, we report the design and bandwidth measurements of micro-OLEDs with active area of 40 × 40μm2. For this OLED, a cut-off frequency up to 459 MHz is observed. Secondly, by applying Direct Current Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) with adaptive bit and energy loading techniques, a data rate of 2.85 Gb/s is achieved. The increase of bandwidth and throughput reported in the current work are attributed to the improvements at the material, device and transmission levels. At the material level, a low work function Calcium cathode and ALD encapsulation of OLED is considered. At the device level, the active area is reduced in size and the OLEDs thickness is optimized. At the transmission level, parameters such as bias voltage, modulation amplitude and clipping have been fine-tuned to obtain high data rate