Comparing Radiation Doses in CBCT and Medical CT Imaging for Dental Applications.

Background: Dental imaging plays a crucial role in diagnosis and treatment planning, with cone-beam computed tomography (CBCT) and medical computed tomography (CT) being two common modalities. This study aims to compare the radiation doses associated with CBCT and medical CT imaging in dental applications to assess their relative safety and efficacy. Materials and Methods: We conducted a retrospective study using data from 100 patients who underwent both CBCT and medical CT scans for dental purposes. The radiation doses were measured in terms of dose-length product (DLP) for medical CT and dose-area product (DAP) for CBCT. The effective dose (ED) was calculated using appropriate conversion factors. Patient demographics, scan parameters, and radiation doses were recorded and analyzed. Results: The results indicated that the mean DLP for medical CT scans was 220 mGycm, whereas the mean DAP for CBCT scans was 150 mGycm². The corresponding mean effective doses for medical CT and CBCT were 2.5 mSv and 1.8 mSv, respectively. The radiation dose from CBCT was found to be approximately 28% lower than that from medical CT. Conclusion: This study demonstrates that CBCT imaging for dental applications results in significantly lower radiation doses compared to medical CT. While both modalities provide valuable diagnostic information, the choice of imaging technique should consider the balance between diagnostic quality and radiation exposure, especially for pediatric and high-risk patients. Dental practitioners should be aware of the potential dose reduction benefits associated with CBCT when appropriate for the clinical scenario.

Land use planning to support climate change adaptation in threatened plant communities.

Among the many causes of habitat loss, urbanization coupled with climate change has produced some of the greatest local extinction rates and has led to the loss of many native species. Managing native vegetation in a rapidly expanding urban setting requires land management strategies that are cognizant of these impacts and how species and communities may adapt to a future climate. Here, we demonstrate how identifying climate refugia for threatened vegetation communities in an urban matrix can be used to support management decisions by local government authorities under the dual pressures of urban expansion and climate change. This research was focused on a local government area in New South Wales, Australia, that is undergoing significant residential, commercial and agricultural expansion resulting in the transition of native forest to other more intensive land-uses. Our results indicate that the key drivers of change from native vegetation to urban and agriculture classes were population density and the proximity to urban areas. We found two of the most cleared vegetation community types are physically restricted to land owned or managed by council, suggesting their long-term ecological viability is uncertain under a warming climate. We propose that land use planning decisions must recognize the compounding spatial and temporal pressures of urban development, land clearing and climate change, and how current policy responses, such as biodiversity offsetting, can respond positively to habitat shifts in order to secure the longevity of important ecological communities.

Evaluation of co-polyaniline nanocomposite thin films as humidity sensor.

Spin coated films of Co-Polyaniline nanocomposite are evaluated for their transmission properties using He-Ne laser for humidity sensing. The thickness (17-29 microm) of the films is varied by multiple deposition of Co-Polyaniline nanocomposite on a glass substrate. The samples exhibit typically two to three regions in their sensitivity curve when tested in the relative humidity (RH) range of 20-95%. The sensitivity ranges from 0.1 mV/%RH to 12.26 mV/%RH for lower to higher thickness. The sensors show quick response of 8s (20-95%RH), and a recovery time of 1 min (95-20%RH) with good repeatability, reproducibility and low hysteresis effect. The sensitivity of the sensor increases with humidity and thickness. Material characterization is done by X-ray diffraction (XRD), scanning electron micrograph (SEM) and Fourier transform infra-red spectroscopy (FTIR).

Fabrication of sucrose biosensor based on single mode planar optical waveguide using co-immobilized plant invertase and GOD.

In present studies, the new optical sensing platform based on optical planar waveguide (OPWG) for sucrose estimation was reported. An evanescent-wave biosensor was designed by using novel agarose-guar gum (AG) biopolymer composite sol-gel with entrapped enzymes (acid invertase (INV) and glucose oxidase (GOD)). Partially purified watermelon invertase isolated from Citrullus vulgaris fruit (specific activity 832 units mg(-1)) in combination with GOD was physically entrapped in AG sol-gel and cladded on the surface of optical planar waveguide. Na(+)-K(+) ion-exchanged glass optical waveguides were prepared and employed for the fabrication of sucrose biosensor. By addressing the enzyme modified waveguide structure with, the optogeometric properties of adsorbed enzyme layer (12 microm) at the sensor solid-liquid interface were studied. The OPWG sensor with short response time (110 s) was characterized using the 0.2M acetate buffer, pH 5.5. The fabricated sucrose sensor showed concentration dependent linear response in the range 1 x 10(-10) to 1 x 10(-6)M of sucrose. Lower limit of detection of this novel AG-INV-GOD cladded OPWG sensor was found to be 2.5 x 10(-11)M sucrose, which indicates that the developed biosensor has higher sensitivity towards sucrose as compared to earlier reported sensors using various transducer systems. Biochips when stored at room temperature, showed high stability for 81 days with 80% retention of original sensitivity. These sucrose sensing biochips showed good operational efficiency for 10 cycles. The proper confinement of acid invertase and glucose oxidase in hydrogel composite was confirmed by scanning electron microscopy (SEM) images. The constructed OPWG sensor is versatile, easy to fabricate and can be used for sucrose measurements with very high sensitivity.