94 research outputs found
Controlling target brain regions by optimal selection of input nodes
Get PDFThe network control theory framework holds great potential to inform neurostimulation experiments aimed at inducing desired activity states in the brain. However, the current applicability of the framework is limited by inappropriate modeling of brain dynamics, and an overly ambitious focus on whole-brain activity control. In this work, we leverage recent progress in linear modeling of brain dynamics (effective connectivity) and we exploit the concept of target controllability to focus on the control of a single region or a small subnetwork of nodes. We discuss when control may be possible with a reasonably low energy cost and few stimulation loci, and give general predictions on where to stimulate depending on the subset of regions one wishes to control. Importantly, using the robustly asymmetric effective connectome instead of the symmetric structural connectome (as in previous research), we highlight the fundamentally different roles in- and out-hubs have in the control problem, and the relevance of inhibitory connections. The large degree of inter-individual variation in the effective connectome implies that the control problem is best formulated at the individual level, but we discuss to what extent group results may still prove useful.Compared to healthy individuals, patients suffering from neurological diseases generally present widely altered brain activity patterns. A promising way to help these people restore a normal brain activity balance is using brain stimulation. As brain areas are interconnected in an intricate web, locally stimulating one or more brain areas can trigger effects across several distant locations, thus evoking a complex response. To achieve a specific response, one should know where (which stimulation sites) to stimulate. Several authors have proposed to solve this puzzle by using a computational model of brain activity together with control theory, a mathematical paradigm to design perturbations with desired effects on a dynamical system. Using an accurate model of brain activity fitted to experimental data from functional magnetic resonance imaging, we show that evoking arbitrary activity patterns in the whole brain requires stimulating a large number of brain areas simultaneously, which is unfeasible with current technology. One can nevertheless focus on a more affordable objective, controlling the activity of a small set of target regions. We discuss how to optimally select stimulation sites (so as to minimize the stimulation intensity) depending on the choice of the target regions, and on the structure of the brain connectivity network
Hypolipidemic and antioxidant potency of heat processed turmeric and red pepper in experimental Rats
No full textThe hypocholesterolemic and antioxidant potency of both raw and pressure-cooked turmeric and red
pepper were evaluated in experimental rats rendered hypercholesterolemic by feeding 0.5% cholesterol
enriched diet and maintained for 8 weeks on 5% spice diet. Dietary turmeric and red pepper, either raw
or heat processed significantly countered the extent of hypercholesterolemia. Serum total cholesterol
was 31 and 32% lower as a result of feeding raw and heat processed turmeric. The same was lower by
16 and 23% in animal groups fed raw and heat processed red pepper. The reduction in blood
cholesterol brought about by these two dietary spices was predominantly in the LDL-cholesterol
fraction. Dietary red pepper, both raw and heat processed fully countered the increase in serum
triglyceride content of hypercholesterolemic rats. Increase in hepatic cholesterol in
hypercholesterolemic animals was moderately countered by dietary red pepper, either raw or heat
processed. Both dietary turmeric as well as red pepper significantly countered the increase in hepatic
triglyceride level in hypercholesterolemic rats. Total thiols in serum were slightly but significantly
increased by raw turmeric and raw red pepper both in basal and in hypercholesterolemic rats, but not
by heat processed spices. Serum a-tocopherol was significantly enhanced (81 - 113%) by both dietary
turmeric and red pepper in hyper-cholesterolemic animals. Hepatic lipid peroxides were significantly
lower (9 - 15%) as a result of dietary turmeric and red pepper in hypercholesterolemic situation. Thus,
the results of this animal study suggested that although heat processing of turmeric and red pepper by
pressure cooking resulted in a considerable loss of the active principles – curcumin and capsaicin, the
hypolipidemic potency or the antioxidant potency of the parent spices were not significantly
compromised
Hepatoprotective Effect of Curcumin and Capsaicin against Lipopolysaccharide Induced Liver Damage in Mice
No full textProtective effect of dietary curcumin and capsaicin on induced oxidation of low-density lipoprotein, iron-induced hepatotoxicity and carrageenan-induced inflammation in experimental rats.
No full textThe beneficial influence of dietary curcumin, capsaicin and their combination on the susceptibility of low-density lipoprotein (LDL) to oxidation was examined in an animal study. Individually, both dietary curcumin and capsaicin significantly inhibited the in vivo iron-induced LDL oxidation, as well as copper-induced oxidation of LDL in vitro. The protective effect of the combination of curcumin and capsaicin on LDL oxidation was greater than that of individual compounds. This protective influence of spice principles was also indicated by the relative anodic electrophoretic mobility of oxidized LDL on agarose gel. In another study, rats injected with iron showed hepatic toxicity as measured by an increase in lipid peroxides and elevated serum enzymes, alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase. Dietary curcumin, capsaicin and their combination reduced the activities of these enzymes, and lowered the liver lipid peroxide level, indicating amelioration of the severity of iron-induced hepatotoxicity. In yet another study, a comparison of the extent of carrageenan-induced paw inflammation showed that both dietary curcumin and capsaicin moderately lowered inflammation, while the spice principles in combination were more effective. Dietary curcumin and capsaicin significantly decreased the activity of 5'-lipoxygenase activity in the polymorphonuclear lymphocytes in carrageenan-injected rats, the decrease being even higher in the case of combination of these two spice principles. Results suggest that dietary curcumin and capsaicin individually are protective to LDL oxidation both in vivo and in vitro, to iron-induced hepatotoxicity and to carrageenan-induced inflammation. This beneficial effect was higher when the two compounds were fed in combination
Molecular dynamics and Conformational flexibility in Heat Shock Protein 60.2 of Mycobacterium tuberculosis
Get PDFHSP 60.2 plays important role in pathogenesis of Mycobacterium tuberculosis causing tuberculosis. This chaperonin comprises of three domains namely-apical, intermediate and equatorial which assists in proper protein folding thus preventing aggregation of unfolded polypeptides. To evaluate the structural changes during protein folding, conformations of HSP 60.2 were monitored during 10 ns time scale. Molecular dynamic simulations are used to study the large amount of molecular and biomolecular conformations with the use of high end computational assistance. The Principal component analysis and clustering techniques are used for revealing major conformational changes that occur in the MD simulation. Normal mode analysis was also performed to study the conformation and direction of motion of a protein under study for a large time scale simulation. These studies suggest that functional behavior of protein that depends on the structure. Chaperonin 60.2 is not only plays a role as protein folding machinery, but also an immunologically important biomolecule. Hence it is provided and drawn a clear path between role of chaperon in protein folding and their role in the infection showing the immunological importance of Heat Shock Protein 60.2
Frequency reconfigurable rectangular patch antenna for cognitive radio applications
Get PDFA frequency reconfigurable microstrip transformed rectangular patch antenna consisting of two slots able to radiate in S-band and C-band is proposed. Spectrum occupancy is first analyzed using the data from literature and internet sources and hence spectrum holes are identified. A rectangular radiating patch is then designed for 5.8 GHz resonant frequency. A coaxial feed is used in the bottom by a suitable feed point. Two slots at an angle of +45 degree are made at the two corners. The electrical length of the patch is changed by using two varactor diodes in the slots. The varactors enable frequency reconfiguration in the band of frequencies that are unused or the spectral occupancy is very less. The return loss, voltage standing wave ratio (VSWR), and 2D-radiation patterns are analyzed for various values of the capacitances. high-frequency structure simulator (HFSS) is used for simulation. FR4 substrate which is economical, is used with height, h=1.6 mm, width W=25.33 mm, and length L=21.34 mm. On the substrate the rectangular patch is of width 15.73 mm and length 11.74 mm. The return loss and radiation patterns for different values of capacitances is presented. The tunability ratio obtained is 1.93. The results obtained agree with the standards
EVALUATION OF IN VITRO ANTI-INFLAMMATORY ACTIVITY OF STEM BARK EXTRACTS OF MESUA FERREA LINN.
Get PDFObjective: Phytochemical evaluation and in vitro anti-inflammatory activity of stem bark extracts of Mesua ferrea Linn.Methods: Petroleum ether, chloroform, and 80% ethanol extracts were used for in-vitro bioassays: such as Human red blood cells membrane stabilization, protein inhibitor, inhibition of egg albumin and anti-lipoxygenase assay to evaluate their anti-inflammatory potential.Results: Phytochemical analysis revealed the presence of phenols, flavonoids, alkaloids, steroids, saponins, tannins, glycosides, and terpenoids. The petroleum ether, chloroform, and 80% ethanol extracts showed significant reduction in inflammation at different 100, 200 and 500μg/ml compared to standard drug indomethacin (100μg/ml).Conclusion: Based on the results, it can be concluded that the 80% ethanol extract of stem bark of Mesua ferrea Linn. (M. ferrea) exhibited significant anti-inflammatory activity compared to petroleum ether and chloroform extracts.Â
The neuropsychiatric aspects of influenza/swine flu: A selective review
No full textThe world witnessed the influenza virus during the seasonal epidemics and pandemics. The current strain of H1N1 (swine flu) pandemic is believed to be the legacy of the influenza pandemic (1918-19). The influenza virus has been implicated in many neuropsychiatric disorders. In view of the recent pandemic, it would be interesting to review the neuropsychiatric aspects of influenza, specifically swine flu. Author used popular search engine ′PUBMED′ to search for published articles with different MeSH terms using Boolean operator (AND). Among these, a selective review of the published literature was done. Acute manifestations of swine flu varied from behavioral changes, fear of misdiagnosis during outbreak, neurological features like seizures, encephalopathy, encephalitis, transverse myelitis, aseptic meningitis, multiple sclerosis, and Guillian-Barre Syndrome. Among the chronic manifestations, schizophrenia, Parkinson′s disease, mood disorder, dementia, and mental retardation have been hypothesized. Further research is required to understand the etiological hypothesis of the chronic manifestations of influenza. The author urges neuroscientists around the world to make use of the current swine flu pandemic as an opportunity for further research
Biogenic synthesis of fluorescent silver nanoparticles using Melastoma Malabathricum flower extract
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