432 research outputs found

    Joint watermarking and encryption of color images in the Fibonacci-Haar domain

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    A novel method for watermarking and ciphering color images, based on the joint use of a key-dependent wavelet transform with a secure cryptographic scheme, is presented. The system allows to watermark encrypted data without requiring the knowledge of the original data and also to cipher watermarked data without damaging the embedded signal. Since different areas of the proposed transform domain are used for encryption and watermarking, the extraction of the hidden information can be performed without deciphering the cover data and it is also possible to decipher watermarked data without removing the watermark. Experimental results show the effectiveness of the proposed scheme

    COVID-19 lockdown: impact on online gambling, online shopping, web navigation and online pornography

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    Background: The COVID-19 pandemic and control measures may have had an impact on unpleasant emotions experimented during the lockdown (LD). This may have increased the number of hours spent online and could have impacted the quality of the enacted behavior, in terms of loss of control of Internet use. In this online survey, we were interested in measure how much loss of control was perceived regarding online gambling, online shopping, the fruition of online pornographic content and web navigation.Design and methods: The online survey was carried out during the COVID-19 pandemic in the post-lockdown and 1232 subjects participated in the survey. In the participating sample, healthcare workers (HW) were 43.1% of the sample, of which 18.7% were directly involved in the Coronavirus emergency, and 52.3% of the sample is not a HW. Only 0.6% of the sample gambled online and 37.5% of those reported losing control of their gambling mode. Most of the sample shopped online during the LD (70.1%), but only 7.2% of those lost control by buying and/or spending more than what they had set themselves.Results: Significant data emerged showing that those who lost control while online shopping also lost control regarding the amount of time spent online (p<0.001); 21.6% of the sample, reported making use of online pornographic material during LD, 4.7% of them stated that the frequency increased and 5.1% reported losing control by having spent more money or more time than what was intended. Finally, 44.7% of the sample have experienced loss of control during the web navigation. Furthermore, during the LD 67.8% of the sample reports having experienced unpleasant emotions. Of these, 8.4% state that they enacted behaviors such as online gambling, online shopping, online pornographic material viewing and web navigation to counter their negative emotions. Interestingly, we found a correlation between loss of control during web navigation and online shopping and the emotional states “upset”, “scared” and “restless” (p<0.05).Conclusion: To conclude, there was no significant increase in potentially addictive behaviors, nor an increase in loss of control of these behaviors when enacted online. However, the loss of control in online shopping and web navigation was significantly correlated to the unpleasant emotional states of nervousness, fear and restlessness, whereas those who reported feeling strong and able to handle the situation experienced a lower loss of control in their web navigation. These correlations may suggest that these online behaviors may act as modulators of unpleasant emotional states

    Manual and semi-automated approaches to MIBG myocardial scintigraphy in patients with Parkinson’s disease

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    OBJECTIVE: This study investigates the effects of manual and semi-automatic methods for assessing MIBG semi-quantitative indices in a clinical setting. MATERIALS AND METHODS: We included (123)I-MIBG scans obtained in 35 patients with idiopathic Parkinson’s Disease. Early and late heart-to-mediastinum (H/M) ratios were calculated from (123)I-MIBG images using regions of interest (ROIs) placed over the heart and the mediastinum. The ROIs were derived using two approaches: (i) manually drawn and (ii) semi-automatic fixed-size ROIs using anatomical landmarks. Expert, moderate-expert, and not expert raters applied the ROIs procedures and interpreted the (123)I-MIBG images. We evaluated the inter and intra-rater agreements in assessing (123)I-MIBG H/M ratios. RESULTS: A moderate agreement in the raters’ classification of pathological and non-pathological scores emerged regarding early and late H/M ratio values (Îș = 0.45 and 0.69 respectively), applying the manual method, while the early and late H/M ratios obtained with the semi-automatic method reached a good agreement among observers (Îș = 0.78). Cohen-Kappa values revealed that the semi-automatic method improved the agreement between expert and inexpert raters: the agreement improved from a minimum of 0.29 (fair, for early H/M) and 0.69 (substantial, in late H/M) with the manual method, to 0.90 (perfect, in early H/M) and 0.87 (perfect, in late H/M) with the semi-automatic method. CONCLUSION: The use of the semi-automatic method improves the agreement among raters in classifying’ H/M ratios as pathological or non-pathological, namely for inexpert readers. These results have important implications for semi-quantitative assessment of (123)I-MIBG images in clinical routine

    Metabolic connectivity of resting-state networks in alpha synucleinopathies, from prodromal to dementia phase

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    Previous evidence suggests that the derangement of large-scale brain networks reflects structural, molecular, and functional mechanisms underlying neurodegenerative diseases. Although the alterations of multiple large-scale brain networks in Parkinson’s disease (PD) and Dementia with Lewy Bodies (DLB) are reported, a comprehensive study on connectivity reconfiguration starting from the preclinical phase is still lacking. We aimed to investigate shared and disease-specific changes in the large-scale networks across the Lewy Bodies (LB) disorders spectrum using a brain metabolic connectivity approach. We included 30 patients with isolated REM sleep behavior disorder (iRBD), 28 with stable PD, 30 with DLB, and 30 healthy controls for comparison. We applied seed-based interregional correlation analyses (IRCA) to evaluate the metabolic connectivity in the large-scale resting-state networks, as assessed by [18F]FDG-PET, in each clinical group compared to controls. We assessed metabolic connectivity changes by applying the IRCA and specific connectivity metrics, such as the weighted and unweighted Dice similarity coefficients (DC), for the topographical similarities. All the investigated large-scale brain resting-state networks showed metabolic connectivity alterations, supporting the widespread involvement of brain connectivity within the alpha-synuclein spectrum. Connectivity alterations were already evident in iRBD, severely affecting the posterior default mode, attentive and limbic networks. Strong similarities emerged in iRBD and DLB that showed comparable connectivity alterations in most large-scale networks, particularly in the posterior default mode and attentive networks. Contrarily, PD showed the main connectivity alterations limited to motor and somatosensory networks. The present findings reveal that metabolic connectivity alterations in the large-scale networks are already present in the early iRBD phase, resembling the DLB metabolic connectivity changes. This suggests and confirms iRBD as a risk condition for progression to the severe LB disease phenotype. Of note, the neurobiology of stable PD supports its more benign phenotype

    OS RISCOS DA AUTOMEDICAÇÃO

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    Cognitive Reserve in Isolated Rapid Eye-Movement Sleep Behavior Disorder

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    Isolated rapid-eye-movement sleep behaviour disorder (RBD) is considered the prodromal stage of α-synucleinopathies (e.g., Parkinson’s disease and dementia with Lewy bodies); however, iRBD patients show a wide variety in the progression timing (5–15 years). The model of cognitive reserve (CR) might contribute to explaining this phenomenon. Our exploratory study aimed to evaluate, for the first time, the impact of CR level on cognitive performance in polysomnography-confirmed iRBD patients. Fifty-five iRBD patients (mean age ± SD: 66.38 ± 7.51; M/F 44/11) underwent clinical and neuropsychological evaluations at the time of diagnosis. The CR Index questionnaire was part of the clinical assessment. We found that iRBD patients with high levels of CR showed: (i) the lowest percentage of mild cognitive impairment (10%), and (ii) the best performance in visuo-constructive and verbal memory functions (i.e., the recall of the Rey–Osterrieth complex figure test). Our results suggest that CR might help iRBD patients better cope with the cognitive decline related to the neurodegenerative process, providing the first preliminary findings supporting CR as a possible protective factor in this condition. This might pave the way for future longitudinal studies to evaluate the role of CR as a modulating factor in the timing of iRBD conversion and cognitive deterioration development.</p

    Study of Detection Limits of Carbonate Phases in Mixtures with Basaltic-like Fine Regolith in the MIR (1–5.5 ”m) Spectral Range

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    The presence of minerals formed under the occurrence of liquid water during the first billion years on Mars was a key discovery, but there is still a large number of open issues that make the study of these mineral deposits a main focus of remote sensing and laboratory studies. Moreover, even though there is extensive research related to the study of the spectral behavior of mixtures, we still lack a full understanding of the problem. The main goal of this work is the analysis of the detection limits of hydrated and carbonate phases within mixtures with basaltic-like fine regolith in the spectral region 1.0–5.5 ”m (1818–10,000 cm−1). We selected two different basalt samples and mixed them with two carbonate phases: a dolomite and a calcite. Spectral features have been investigated isolating the main carbonate absorption features and overtones; deriving trends of spectral parameters such as band depth, band area, full-width-half-maximum; percentage and grain size variations. The results obtained in this work show how the presence of a basaltic component can strongly influence the appearance of the hydrated and carbonate features showing different trends and intensities depending on the grain size and percentage of the carbonate components

    Neurobiological Dysfunctional Substrates for the Self-Medication Hypothesis in Adult Individuals with Attention-Deficit Hyperactivity Disorder and Cocaine Use Disorder:A Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography Study

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    Objectives: Attention-deficit hyperactivity disorder (ADHD) in adulthood shows high co-occurrence rates with cocaine use disorder (CoUD). The self-medication hypothesis (SMH) provides a theoretical explanation for this comorbidity. This study investigates the neurobiological mechanisms that could support SMH in adult patients with attention-deficit hyperactivity disorder with cocaine use disorder (ADHD–CoUD).Materials and Methods: We included 19 ADHD–CoUD patients (84.2% male; age: 32.11 years [7.18]) and 16 CoUD patients (68.7% male; age: 36.63 years [8.12]). All subjects underwent a fluorine-18-fluorodeoxyglucose positron emission tomography (18F-FDG PET) brain scan. We tested brain metabolism differences between ADHD–CoUD and CoUD patients using voxel-based and regions of interest (ROIs)-based analyses. The correlation between dependence/abstinence duration and regional brain metabolism was also assessed in the two groups. Lastly, we investigated the integrity of brain metabolic connectivity of mesocorticolimbic and nigrostriatal dopaminergic systems, and large-scale brain networks involved in ADHD and addictions.Results: The voxel-wise and ROIs-based approaches showed that ADHD–CoUD patients had a lower metabolism in the thalamus and increased metabolism in the amygdala and parahippocampus, bilaterally, than CoUD subjects and healthy controls (HCs). Metabolism in the thalamus negatively correlated with years of dependence in ADHD–CoUD patients. Moreover, connectivity analyses revealed that ADHD–CoUD patients had a more preserved metabolic connectivity than CoUD patients in the dopaminergic networks and large-scale networks involved in self-regulation mechanisms of attention and behaviors (i.e., anterior default mode network [ADMN], executive network [ECN], and anterior salience network [aSAN]).Conclusions: We demonstrated distinct neuropathological substrates underlying substance-use behaviors in ADHD–CoUD and CoUD patients. Furthermore, we provided neurobiological evidence in support of SMH, demonstrating that ADHD–CoUD patients might experience short-term advantages of cocaine assumption (i.e., compensation of dopaminergic deficiency and related cognitive-behavioral deficits).</p
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