Evaluation of yttrium-90 positron emission tomography dosimetry

Purpose: Radioembolization is a novel treatment which utilizes the liver\u27s unique dual system blood supply to trap yttrium-90 (90Y) microspheres in microvasculature near liver tumors. Radioembolization dose planning and dosimetry are based on crude, inaccurate assumptions due to the lack of knowledge of patient specific 90Y microsphere distribution. In recent years, the very small 3.1867e-5 internal pair production decay branch of 90Y has been shown to allow for positron emission tomography (PET) imaging following radioembolization. This work explores the accuracy and limitation of 90Y PET imaging due to the extremely low signal to noise (SNR) ratio associated with 90Y and verifies the accuracy of using these PET images for 3-dimensional (3D) dosimetry. ^ Material and Methods: PET acquisitions of a phantom containing 90Y filled cylindrical inserts were acquired to determine quantitative accuracy of the PET images to measure 90Y activity. Numerous reconstruction algorithms were used to determine the optimal protocol to balance image noise and accuracy. A GATE model of the PET scanner was used to evaluate the origin of prompt signal and random noise coincidence counts in these PET acquisitions. PET images were converted to dose maps using standard S-kernel convolution. Polymer gel dosimetry was used to validate the 3D dose map results. Furthermore, PET, with associated CT images, were used as input data into MC simulations to model dose rates surrounding patients for future patient release studies. A Siemens® Biograph 64 TruePoint PET/CT was used for all acquisitions and reconstructions. ^Results: The phantom study determined Siemens® OSEM-PSF algorithm, known as TrueX, with 2 iterations and 14 subsets had the optimal balance of noise and accuracy. Using this reconstruction algorithm, the PET images were found to accurately measure activity and calculated dose within 10% when 90Y concentration was above the minimum detectable concentrations (MDC) of 1 MBq/ml. However, this reconstruction algorithm was shown to have a positive bias in areas where concentration was below the MDC due to truncation of negative sinogram bin values caused by statistical noise in the random correction. Polymer gel dosimetry verified the accuracy of PET dose maps but also identified a limitation in cases of highly gradient distributions due to the PET spatial resolution spreading of measured activity. Additionally, external dose rates were found to be accurately predicted through use of 90Y PET/CT images as inputs into a MC simulation.Conclusion: Research in 90Y PET/CT has quickly been expanding over recent years as a feasible method to provide liver distribution of 90Y following radioembolization. This study demonstrates the accuracy and limitations of the use of these 90Y PET/CT images in patient specific qualitative dosimetry

Superconductivity at 38 K in Iron-Based Compound with Platinum-Arsenide Layers Ca10(Pt4As8)(Fe2-xPtxAs2)5

We report superconductivity in novel iron-based compounds Ca10(PtnAs8)(Fe2-xPtxAs2)5 with n = 3 and 4. Both compounds crystallize in triclinic structures (space group P-1), in which Fe2As2 layers alternate with PtnAs8 spacer layers. Superconductivity with a transition temperature of 38 K is observed in the n = 4 compound with a Pt content of x ~ 0.36 in the Fe2As2 layers. The compound with n = 3 exhibits superconductivity at 13 K.Comment: OPEN SELECT article, 11 pages, 5 figures, 2 table

Effects of nicotine on alcohol drinking in female mice selectively-bred for high or low alcohol preference

Background Studies show that repeated nicotine use associates with high alcohol consumption in humans, and that nicotine exposure sometimes increases alcohol consumption in animal models. However, the relative roles of genetic predisposition to high alcohol consumption, the alcohol drinking patterns, and the timing of nicotine exposure both with respect to alcohol drinking and developmental stage remain unclear. The studies here manipulated all these variables, using mice selectively bred for differences in free-choice alcohol consumption to elucidate the role of genetics and nicotine exposure in alcohol consumption behaviors. Methods In Experiments 1 and 2, we assessed the effects of repeated nicotine (0, 0.5 or 1.5 mg/kg) injections immediately before binge-like (drinking-in-the-dark; Experiment 1) or during free-choice alcohol access (Experiment 2) on these alcohol drinking behaviors (immediately after injections and during re-exposure to alcohol access 14 days later) in adult high- (HAP2) and low-alcohol preferring (LAP2) female mice (co-exposure model). In Experiments 3 and 4, we assessed the effects of repeated nicotine (0, 0.5 or 1.5 mg/kg) injections 14 days prior to binge-like and free-choice alcohol access on these alcohol drinking behaviors in adolescent HAP2 and LAP2 female mice (Experiment 3) or adult HAP2 female mice (Experiment 4). Results In Experiment 1, we found that repeated nicotine (0.5 and 1.5 mg/kg) and alcohol co-exposure significantly increased binge-like drinking behavior in HAP2 but not LAP2 mice during the re-exposure phase after a 14-day abstinence period. In Experiment 2, 1.5 mg/kg nicotine injections significantly reduced free-choice alcohol intake and preference in the 3rd hour post-injection in HAP2 but not LAP2 mice. No significant effects of nicotine treatment on binge-like or free-choice alcohol drinking were observed in Experiments 3 and 4. Conclusions These results show that the temporal parameters of nicotine and alcohol exposure, pattern of alcohol access, and genetic predisposition for alcohol preference influence nicotine's effects on alcohol consumption. These findings in selectively bred mice suggest that humans with a genetic history of alcohol-use disorders may be more vulnerable to develop nicotine and alcohol co-use disorders

Cardiometabolic Health Among Adult Offspring of Hypertensive Pregnancies: The Cardiovascular Risk in Young Finns Study.

BACKGROUND: Cardiometabolic health among adult offspring of hypertensive disorders of pregnancy (HDP) is relatively unknown. We hypothesized that offspring of HDP would have abnormalities in the retinal microvasculature and cardiac structure by midadulthood. METHODS AND RESULTS: The Cardiovascular Risk in Young Finns Study included randomly selected children from 5 Finnish university cities. The mean age of participants was 40 years (range 34-49 years) at the time of retinal photography and cardiac assessment. Offspring born ≥37 weeks of gestation and appropriate for gestational age (n=1006) were included. Offspring of HDP had higher systolic blood pressure (β=4.68, P<0.001), body mass index (β=1.25, P=0.009), and waist circumference (β=0.25, P=0.042), compared with offspring of normotensive pregnancies. However, no differences in fasting glucose, insulin, lipid profile, carotid intima media thickness, or brachial artery flow-mediated dilatation were shown. Retinal arteriolar diameters were narrower (β=-0.43, P=0.009) and longer (β=32.5, P=0.023) and the arteriolar length-to-diameter ratio was higher (β=2.32, P=0.006) among offspring of HDP, after adjustment for age and sex. Left atrial volume indexed to body surface area (β=1.34, P=0.040) was increased. Adjustment for the confounding effects of birth weight, body mass index, smoking and socioeconomic status, and the mediating effect of hypertension had little impact on the associations. CONCLUSIONS: Abnormalities of the retinal microvasculature and cardiac structure are seen in offspring of HDP in midadulthood. These findings may need to be considered in future primary prevention strategies of cardiovascular disease among offspring of HDP

Optimality of private quantum channels

We addressed the question of optimality of private quantum channels. We have shown that the Shannon entropy of the classical key necessary to securely transfer the quantum information is lower bounded by the entropy exchange of the private quantum channel $\cal E$ and von Neumann entropy of the ciphertext state $\varrho^{(0)}$. Based on these bounds we have shown that decomposition of private quantum channels into orthogonal unitaries (if exists) is optimizing the entropy. For non-ancillary single qubit PQC we have derived the optimal entropy for arbitrary set of plaintexts. In particular, we have shown that except when the (closure of the) set of plaintexts contains all states, one bit key is sufficient. We characterized and analyzed all the possible single qubit private quantum channels for arbitrary set of plaintexts. For the set of plaintexts consisting of all qubit states we have characterized all possible approximate private quantum channels and we have derived the relation between the security parameter and the corresponding minimal entropy.Comment: no commen

Nutritional factors and gender influence age-related DNA methylation in the human rectal mucosa

Aberrant methylation of CpG islands (CGI) occurs in many genes expressed in colonic epithelial cells, and may contribute to the dysregulation of signalling pathways associated with carcinogenesis. This cross-sectional study assessed the relative importance of age, nutritional exposures and other environmental factors in the development of CGI methylation. Rectal biopsies were obtained from 185 individuals (84 male, 101 female) shown to be free of colorectal disease, and for whom measurements of age, body size, nutritional status and blood cell counts were available. We used quantitative DNA methylation analysis combined with multivariate modelling to investigate the relationships between nutritional, anthropometric and metabolic factors and the CGI methylation of 11 genes, together with LINE-1 as an index of global DNA methylation. Age was a consistent predictor of CGI methylation for 9/11 genes but significant positive associations with folate status and negative associations with vitamin D and selenium status were also identified for several genes. There was evidence for positive associations with blood monocyte levels and anthropometric factors for some genes. In general, CGI methylation was higher in males than in females and differential effects of age and other factors on methylation in males and females were identified. In conclusion, levels of age-related CGI methylation in the healthy human rectal mucosa are influenced by gender, the availability of folate, vitamin D and selenium, and perhaps by factors related to systemic inflammatio

First-Principles Study for the Anisotropy of Iron-based Superconductors toward Power and Device Applications

Performing the first-principles calculations, we investigate the anisotropy in the superconducting state of iron-based superconductors to gain an insight into their potential applications. The anisotropy ratio $\gamma_\lambda$ of the c-axis penetration depth to the ab-plane one is relatively small in BaFe2As2 and LiFeAs, i.e., $\gamma_\lambda \sim 3$, indicating that the transport applications are promising in these superconductors. On the other hand, in those having perovskite type blocking layers such as Sr2ScFePO3 we find a very large value, $\gamma_\lambda \sim 200$, comparable to that in strongly anisotropic high-Tc cuprate Bi2Sr2CaCu2O{8-\delta}. Thus, the intrinsic Josephson junction stacks are expected to be formed along the c-axis, and novel Josephson effects due to the multi-gap nature are also suggested in these superconductors.Comment: 5 pages, 4 figure

Social marketing and social influences: Using social ecology as a theoretical framework

Social marketing has traditionally been dominated by an individualistic model of design. In this work, the authors apply a social ecology model to the theory and practice of social marketing, demonstrating that a multilevel framework is required to fully expose and account for the complexity of sociocultural and environmental effects. The authors have generated a diagnostic tool for this use. The paper then provides a detailed demonstration of the potential power of the tool by applying it to three illustrative case studies: one on encouraging safer driving, the second promoting sustainable travel, and the third increasing early detection of lung cancer. © 2010 Westburn Publishers Ltd

A Tilted Axis: Maladaptive Inflammation and HPA Axis Dysfunction Contribute to Consequences of TBI

Each year approximately 1.7 million people sustain a traumatic brain injury (TBI) in the US alone. Associated with these head injuries is a high prevalence of neuropsychiatric symptoms including irritability, depression, and anxiety. Neuroinflammation, due in part to microglia, can worsen or even cause neuropsychiatric disorders after TBI. For example, mounting evidence demonstrates that microglia become “primed” or hyper-reactive with an exaggerated pro-inflammatory phenotype following multiple immune challenges. Microglial priming occurs after experimental TBI and correlates with the emergence of depressive-like behavior as well as cognitive dysfunction. Critically, immune challenges are various and include illness, aging, and stress. The collective influence of any combination of these immune challenges shapes the neuroimmune environment and the response to TBI. For example, stress reliably induces inflammation and could therefore be a gateway to altered neuropathology and behavioral decline following TBI. Given the increasing incidence of stress-related psychiatric disorders after TBI, the degree in which stress affects outcome is of particular interest. This review aims to highlight the role of the hypothalamic-pituitary-adrenal (HPA) axis as a key mediator of stress-immune pathway communication following TBI. We will first describe maladaptive neuroinflammation after TBI and how stress contributes to inflammation through both anti- and pro-inflammatory mechanisms. Clinical and experimental data describing HPA-axis dysfunction and consequences of altered stress responses after TBI will be discussed. Lastly, we will review common stress models used after TBI that could better elucidate the relationship between HPA axis dysfunction and maladaptive inflammation following TBI. Together, the studies described in this review suggest that HPA axis dysfunction after brain injury is prevalent and contributes to the dynamic nature of the neuroinflammatory response to brain injury. Experimental stressors that directly engage the HPA axis represent important areas for future research to better define the role of stress-immune pathways in mediating outcome following TBI