217 research outputs found

    Brain Activation by Visual Food-Related Stimuli and Correlations with Metabolic and Hormonal Parameters: A fMRI Study

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    Regional brain activity in 15 healthy, normal weight males during processing of visual food stimuli in a satiated and a hungry state was examined and correlated with neuroendocrine factors known to be involved in hunger and satiated states. Two functional Magnetic Resonance Imaging (fMRI) sessions were performed with a one week interval, after overnight fasting or 1 hour after a standardized meal. Blood samples and appetite assessment were obtained after each fMRI session. Main effects of processing food versus non-food stimuli were observed in the ventral visual stream, including the fusiform gyrus and hippocampal areas bilaterally, significantly more in the fasting state. Leptin concentration correlated negatively with activity in the left hippocampal area and right insula during the satiation condition. A positive correlation between ghrelin and "thought of food" hunger scores were found. The positive correlation between ghrelin and food related activation in the insula areas and the right hippocampus during fasting did not reach significance. Conclusion: The increased activation of food vs non-food pictures in the ventral visual stream reflects increased salience of food pictures when subjects are hungry. Leptin was associated with activations in areas involved in processing of new information and emotion. © Jakobsdottir et al

    Time-domain Physical Unclonable Functions

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    One can replace one-way functions (also known as hash functions) commonlyfound in cryptography with physical processes, known as physical unclonable functions (PUFs). Optical PUFs have been devised based on the complex response ofscattering media to the spatial wavefront. However, such PUFs are intrinsicallyunpractical for use over larger distances. In this project, we design PUFs with atime-domain scattering response (tPUF), whose readout can be performed over asingle spatial mode, in our case an optical fiber. These tPUFs are networks of microring resonators, whose transfer function is highly complex and vary strongly from realization to realization as a result of manufacturing imperfections. Thesedevices are developed for pulses with a very low number of average photons perpulse which negates any attempts at reading out the pulse shape in transit, therebyeliminating eavesdropping. These PUFs can then be used for a variety of applicationsin asymmetric cryptography, such as proof of identity and secure messaging

    Using local and historical data to enhance understanding of spatial and temporal rainfall patterns

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    Farmers face uncertainty in their businesses from many factors, but rainfall is a key determinant of both the nature of the production system and variation in financial returns. Currently, various weather forecasting services are available from the Australian Bureau of Meteorology (BoM) based on about 7000 stations covering all of Australia. Seasonal Climate Forecasts are seen as another tool that can help to improve farm productivity. It is well known that many farmers keep their own rainfall records, and likely that the farmers have a high degree of confidence in their own records. Australian Bureau of Statistics figures indicate that there were possibly 7000 grain related ‘agricultural businesses’ in NSW alone in 2009/10 indicating that there is the potential to increase data density by up to an order of magnitude. This project is part of a broader study to improve rainfall predictions for grain farmers using data collected locally to the users (crowd sourcing). The data is collected directly on farm, and from other sources which may be available. The focus is on the historical data, its collection and analysis, in terms of discerning patterns in time and space which may help provide a local framework, within which coarser scale forecasts can be interpreted and understood. Data will be stored on secure database systems at the University of Sydney. Results indicate that farm data does provide more local detail, temporally and spatially. Deficit and surplus analysis demonstrates the predictive capacity of the local temporal data, despite limited data precluding the definition of ideal criteria and parameters for predictive ‘similar year’ selection. The spatial data demonstrates quantifiable site specific differences from institutional data. Testing across more climate types may allow these differences to be defined within and across regions. Tests for an indicator time period show that farm rainfall in the early part of the growing season (April and May) may indeed be indicative of seasonal condtions, while more data is needed to confirm this. The use of southern oscillation life cycle information to select appropriate years considerably improved the relationships revealed, with a doubling of relationship strength across all climatic types, although the strength of the relationships differed across the climatic types, and the strongest relationships were split between the months of April and May. More extensive analysis, with more data across more BoM districts (and therefore climate classes) will be required to confirm this conclusion, but it appears that farm rainfall records and SOI information can provide an indicator time period to help farmers interpret, refine and utilise seasonal forecasts

    Developmental simulation of the adult cranial morphology of australopithecus sediba.

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    The type specimen of Australopithecus sediba (MH1) is a late juvenile, prompting some commentators to suggest that had it lived to adulthood its morphology would have changed sufficiently so as to render hypotheses regarding its phylogenetic relations suspect. Considering the potentially critical position of this species with regard to the origins of the genus Homo, a deeper understanding of this change is especially vital. As an empirical response to this critique, a developmental simulation of the MH1 cranium was carried out using geometric morphometric techniques to extrapolate adult morphology using extant male and female chimpanzees, gorillas and humans by modelling remaining development. Multivariate comparisons of the simulated adult A. sediba crania with other early hominin taxa indicate that subsequent cranial development primarily reflects development of secondary sexual characteristics and would not likely be substantial enough to alter suggested morphological affinities of A. sediba. This study also illustrates the importance of separating developmental vectors by sex when estimating ontogenetic change. Results of the ontogenetic projections concur with those from mandible morphology, and jointly affirm the taxonomic validity of A. sediba.Andrew W. Mellon Foundation and National Geographic Society.NCS201

    The role of surgery for stage I non-small cell lung cancer in octogenarians in the era of stereotactic body radiotherapy in the Netherlands

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    ObjectivesResection is the standard treatment for stage I non-small cell lung cancer (NSCLC) in operable patients. Stereotactic body radiotherapy (SBRT) is recommended for inoperable patients. A shift from surgery to SBRT is expected in elderly patients due to increased frailty and competing risks. We assessed the current influence of age on treatment decision-making and overall survival (OS).Materials and methodsWe performed a retrospective cohort study using data from patients with clinical stage I NSCLC diagnosed in 2012–2016 and treated with lobectomy, segmentectomy, wedge resection, or SBRT, retrieved from the Netherlands Cancer Registry. Patient characteristics and OS were compared between SBRT and (sub)lobar resection for patients aged 18−79 and ≥80 years.Results and Conclusion8764 patients treated with lobectomy (n = 4648), segmentectomy (n = 122), wedge resection (n = 272), or SBRT (n = 3722) were included. In 2012–2016, SBRT was increasingly used for octogenarians and younger patients from 75.3% to 83.7% and from 30.8% to 43.2%, respectively. Five-year OS in the whole population was 70% after surgery versus 39% after SBRT and 50% versus 27% in octogenarians. After correction for age, gender, year of diagnosis, and clinical T-stage, OS was equal after lobectomy and SBRT in the first 2 years after diagnosis. However, after >2 years, OS was better after lobectomy than after SBRT.SBRT is the prevailing treatment in octogenarians with stage I NSCLC. While surgery is associated with better OS than SBRT, factors other than treatment modality (e.g. comorbidity) may have had a significant impact on survival. The wider application of SBRT in octogenarians likely reflects the frailty of this group. Registries and trials are required to identify key determinants of frailty in this specific population to improve patient selection for surgery or SBRT.Stem cells & developmental biolog

    Changes in Natural Foxp3+Treg but Not Mucosally-Imprinted CD62LnegCD38+Foxp3+Treg in the Circulation of Celiac Disease Patients

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    Background:Celiac disease (CD) is an intestinal inflammation driven by gluten-reactive CD4+ T cells. Due to lack of selective markers it has not been determined whether defects in inducible regulatory T cell (Treg) differentiation are associated with CD. This is of importance as changes in numbers of induced Treg could be indicative of defects in mucosal tolerance development in CD. Recently, we have shown that, after encounter of retinoic acid during differentiation, circulating gut-imprinted T cells express CD62LnegCD38+. Using this new phenotype, we now determined whether alterations occur in the frequency of natural CD62L+Foxp3+ Treg or mucosally-imprinted CD62LnegCD38+Foxp3+ Treg in peripheral blood of CD patients. In particular, we compared pediatric CD, aiming to select for disease at onset, with adult CD.Methods:Cell surface markers, intracellular Foxp3 and Helios were determined by flow cytometry. Foxp3 expression was also detected by immunohistochemistry in duodenal tissue of CD patients.Results:In children, the percentages of peripheral blood CD4+Foxp3+ Treg were comparable between CD patients and healthy age-matched controls. Differentiation between natural and mucosally-imprinted Treg on the basis of CD62L and CD38 did not uncover differences in Foxp3. In adult patients on gluten-free diet and in refractory CD increased percentages of circulating natural CD62L+Foxp3+ Treg, but normal mucosally-imprinted CD62LnegCD38+Foxp3+ Treg frequencies were observed.Conclusions:Our data exclude that significant numeric deficiency of mucosally-imprinted or natural Foxp3+ Treg explains exuberant effector responses in CD. Changes in natural Foxp3+ Treg occur in a subset of adult patients on a gluten-free diet and in refractory CD patients
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