4,780 research outputs found

    Differences of Various Region-of-Interest Methods for Measuring Dopamine Transporter Availability Using T

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    This study was to investigate whether various region-of-interest (ROI) methods for measuring dopamine transporter (DAT) availabilities by single photon emission computed tomography (SPECT) are statistically different, whether results of medical research are thereby influenced, and causes of these differences. Eighty-four healthy adults with Tc99m-TRODAT-1 SPECT and magnetic resonance imaging (MRI) scans were included. Six major analysis approaches were compared: (1) ROI drawn on the coregistered MRI; (2) ROIs drawn on the SPECT images; (3) standard ROI templates; (4) threshold-ROIs; (5) atlas-based mappings with coregistered MRI; and (6) atlas-based mappings with SPECT images. Using the atlas-based approaches we assessed the influence of striatum ROIs by slice-wise and voxel-wise comparisons. In (5) and (6), three partial-volume correction (PVC) methods were also explored. The results showed that DAT availabilities obtained from different methods were closely related but quite different and leaded to significant differences in determining the declines of DAT availability per decade (range: 5.95–11.99%). Use of 3D whole-striatum or more transverse slices could avoid biases in measuring the striatal DAT declines per decade. Atlas-based methods with PVC may be the preferable methods for medical research

    The Relationship between Brown Adipose Tissue Activity and Neoplastic Status: an 18F-FDG PET/CT Study in the Tropics

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    <p>Abstract</p> <p>Background</p> <p>Brown adipose tissue (BAT) has thermogenic potential. For its activation, cold exposure is considered a critical factor though other determinants have also been reported. The purpose of this study was to assess the relationship between neoplastic status and BAT activity by 2-deoxy-2-[18F]fluoro-D-glucose (<sup>18</sup>F-FDG) positron emission tomography/computed tomography (PET/CT) in people living in the tropics, where the influence of outdoor temperature was low.</p> <p>Methods</p> <p><sup>18</sup>F-FDG PET/CT scans were reviewed and the total metabolic activity (TMA) of identified activated BAT quantified. The distribution and TMA of activated BAT were compared between patients with and without a cancer history. The neoplastic status of patients was scored according to their cancer history and <sup>18</sup>F-FDG PET/CT findings. We evaluated the relationships between the TMA of BAT and neoplastic status along with other factors: age, body mass index, fasting blood sugar, gender, and outdoor temperature.</p> <p>Results</p> <p>Thirty of 1740 patients had activated BAT. Those with a cancer history had wider BAT distribution (<it>p </it>= 0.043) and a higher TMA (<it>p </it>= 0.028) than those without. A higher neoplastic status score was associated with a higher average TMA. Multivariate analyses showed that neoplastic status was the only factor significantly associated with the TMA of activated BAT (<it>p </it>= 0.016).</p> <p>Conclusions</p> <p>Neoplastic status is a critical determinant of BAT activity in patients living in the tropics. More active neoplastic status was associated with more vigorous TMA of BAT.</p

    The association between diabetes-related distress and fear of hypoglycaemia in patients with type 2 diabetes mellitus: A cross-sectional descriptive study

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    Aim: The study aimed to explore the association between diabetes-related distress as a dependent variable and fear of hypoglycaemia as a independent variable in Chinese individuals with type 2 diabetes, which can provide a basis for the development of effective nursing interventions. Design: A cross-sectional descriptive study. Methods: Pre-piloted scales were used to determine whether they experienced fear of hypoglycaemia and whether this impacted upon their management of the disease. From June–October 2019, participants were asked to complete the “hypoglycaemia fear survey” and “diabetes distress scales” to assess levels of fear and distress. Stepwise multivariate regression analysis was applied to reveal relationship between distress as a dependent variable and fear as a independent variable. Covariates included demographic, clinical or lifestyle factors. Results: A total of 258 participants were recruited for the survey, and they were characterized by little or no distress (39.53%), moderate distress (45.35%) and high distress (15.12%). The prevalence of moderate to severe distress in patients was 60.47%. Increased diabetes-related distress was strongly correlated with increased fear of hypoglycaemia and closely associated with the scores of the worry and behaviour subscales. These results indicated that 62.3% of diabetes-related distress may be explained by fear of hypoglycaemia. Conclusion: Increased diabetes-related distress is associated with increased fear of hypoglycaemia in individuals with type 2 diabetes

    A False Positive 18F-FDG PET/CT Scan Caused by Breast Silicone Injection

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    We present here the case of a 40-year-old woman with a greater than 10 year prior history of bilateral breast silicone injection and saline bag implantation. Bilateral palpable breast nodules were observed, but the ultrasound scan was suboptimal and the magnetic resonance imaging showed no gadolinium-enhanced tumor. The 18F-FDG PET/CT scan showed a hypermetabolic nodule in the left breast with a 30% increase of 18F-FDG uptake on the delayed imaging, and this mimicked breast cancer. She underwent a left partial mastectomy and the pathology demonstrated a siliconoma

    The association between diabetes-related distress and fear of hypoglycaemia in patients with type 2 diabetes mellitus: A cross-sectional descriptive study

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    Aim: The study aimed to explore the association between diabetes-related distress as a dependent variable and fear of hypoglycaemia as a independent variable in Chinese individuals with type 2 diabetes, which can provide a basis for the development of effective nursing interventions. Design: A cross-sectional descriptive study. Methods: Pre-piloted scales were used to determine whether they experienced fear of hypoglycaemia and whether this impacted upon their management of the disease. From June–October 2019, participants were asked to complete the “hypoglycaemia fear survey” and “diabetes distress scales” to assess levels of fear and distress. Stepwise multivariate regression analysis was applied to reveal relationship between distress as a dependent variable and fear as a independent variable. Covariates included demographic, clinical or lifestyle factors. Results: A total of 258 participants were recruited for the survey, and they were characterized by little or no distress (39.53%), moderate distress (45.35%) and high distress (15.12%). The prevalence of moderate to severe distress in patients was 60.47%. Increased diabetes-related distress was strongly correlated with increased fear of hypoglycaemia and closely associated with the scores of the worry and behaviour subscales. These results indicated that 62.3% of diabetes-related distress may be explained by fear of hypoglycaemia. Conclusion: Increased diabetes-related distress is associated with increased fear of hypoglycaemia in individuals with type 2 diabetes

    Ni(OH)2 Nanoplates Grown on Graphene as Advanced Electrochemical Pseudocapacitor Materials

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    Ni(OH)2 nanocrystals grown on graphene sheets with various degrees of oxidation are investigated as electrochemical pseudocapacitor materials for potential energy storage applications. Single-crystalline Ni(OH)2 hexagonal nanoplates directly grown on lightly-oxidized, electrically-conducting graphene sheets (GS) exhibit a high specific capacitance of ~1335F/g at a charge and discharge current density of 2.8A/g and ~953F/g at 45.7A/g with excellent cycling ability. The high specific capacitance and remarkable rate capability are promising for applications in supercapacitors with both high energy and power densities. Simple physical mixture of pre-synthesized Ni(OH)2 nanoplates and graphene sheets show lower specific capacitance, highlighting the importance of direct growth of nanomaterials on graphene to impart intimate interactions and efficient charge transport between the active nanomaterials and the conducting graphene network. Single-crystalline Ni(OH)2 nanoplates directly grown on graphene sheets also significantly outperform small Ni(OH)2 nanoparticles grown on heavily-oxidized, electrically-insulating graphite oxide (GO), suggesting that the electrochemical performance of these composites are dependent on the quality of graphene substrates and the morphology and crystallinity of the nanomaterials grown on top. These results suggest the importance of rational design and synthesis of graphene-based nanocomposite materials for high-performance energy applications.Comment: Published in JAC

    Reconstructing large running-index inflaton potentials

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    Recent fits of cosmological parameters by the first year Wilkinson Microwave Anisotropy Probe (WMAP) measurement seem to favor a primordial scalar spectrum with a large varying index from blue to red. We use the inflationary flow equations to reconstruct large running-index inflaton potentials and comment on current status on the inflationary flow. We find previous negligence of higher order slow rolling contributions when using the flow equations would lead to unprecise results.Comment: Final version to appear in Class. Quant. Grav. References adde
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