Steganography method based on wavelength for images

In this paper, it is aimed to deal with secure communication problem depends onperceptibility. In data hiding process, imperceptibly is much important issue.Perceptibility measure depends on HVS (Human Visual System) in images, videos. In this case, developing software must be sensitive HVS range. Our method proposes to find appropriate pixels using visible light range's edge for embedding hidden data into coverimage. Other methods which use visible light methods have some difficulties. Our method tries to satisfy these difficulties. It is known that color transition is most critic point forHVS's perceptibility. So, in our method, first step is finding appropriate pixels which are near visible light range's edge value. And then these pixels can be use for embedding hidden data into cover image. Thus, secure communication problem depends on perceptibility can solve effectively

Metabolic Alterations in Parkinson's Disease after Thalamotomy, as Revealed by 1H MR Spectroscopy

Objective: To determine, using proton magnetic resonance spectroscopy ( 1H MRS) whether thalamotomy in patients with Parkinson\u27s disease gives rise to significant changes in regional brain metabolism. Materials and Methods: Fifteen patients each underwent stereotactic thalamotomy for the control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was performed on a 1.5T unit using a STEAM sequence (TR/TM/TE, 2000/14/20 msec), and spectra were obtained from substantia nigra, thalamus and putamen areas, with volumes of interest of 7-8ml, before and after thalamotomy. NAA/Cho, NAA/Cr and Cho/Cr metabolite ratios were calculated from relative peak area measurements, and any changes were recorded and assessed. Results: In the substantia nigra and thalamus, NAA/Cho ratios were generally low. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (\u3c 0.05). In the thalamus of 67% of such patients (10/15), significant decreases were also noted (\u3c 0.05). Conclusion: Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson\u27s disease patients who show clinical improvement following surgery. By highlighting variations in this ratio, 1H MRS may help lead to a better understanding of the pathophysiologic processes occurring in those with Parkinson\u27s disease

Postsynaptic nigrostriatal dopamine receptors and their role in movement regulation

The article presents the hypothesis that nigrostriatal dopamine may regulate movement by modulation of tone and contraction in skeletal muscles through a concentration-dependent influence on the postsynaptic D1 and D2 receptors on the follow manner: nigrostriatal axons innervate both receptor types within the striatal locus somatotopically responsible for motor control in agonist/antagonist muscle pair around a given joint. D1 receptors interact with lower and D2 receptors with higher dopamine concentrations. Synaptic dopamine concentration increases immediately before movement starts. We hypothesize that increasing dopamine concentrations stimulate first the D1 receptors and reduce muscle tone in the antagonist muscle and than stimulate D2 receptors and induce contraction in the agonist muscle. The preceded muscle tone reduction in the antagonist muscle eases the efficient contraction of the agonist. Our hypothesis is applicable for an explanation of physiological movement regulation, different forms of movement pathology and therapeutic drug effects. Further, this hypothesis provides a theoretical basis for experimental investigation of dopaminergic motor control and development of new strategies for treatment of movement disorders