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11.
Background
Continuous theta burst stimulation (cTBS) is a form of repetitive transcranial magnetic stimulation which has been shown to alter cortical excitability in the upper limb representation of primary somatosensory cortex (SI). However, it is unknown whether cTBS modulates cortical excitability within the lower limb representation in SI. The present study investigates the effects of cTBS over the SI lower limb representation on cortical somatosensory evoked potentials (SEPs) and Hoffmann reflex (H-reflex) following tibial nerve stimulation at the knee. SEPs and H-reflex were recorded before and in four time blocks up to 30 minutes following cTBS targeting the lower limb representation within SI.Results
Following cTBS, the P1-N1 first cortical potential was significantly decreased at 12?C16 minutes. CTBS also suppressed the P2-N2 second cortical potential for up to 30 minutes following stimulation. The H-reflex remained statistically unchanged following cTBS although there was a modest suppression observed.Conclusion
We conclude that cTBS decreases cortical excitability of the lower limb representation of SI as evidenced by suppressed SEP amplitude. The duration and magnitude of the cTBS after effects are similar to those observed in upper limb studies. 相似文献12.
Smriti KoodanjeriAjit R Pradhan Lakshmi S KaanumalleV Ramamurthy 《Tetrahedron letters》2003,44(15):3207-3210
1-Naphthyl phenyl acylates upon irradiation in solution yield eight products via β-cleavage process. However, excitation of these molecules as included in γ-cyclodextrin results in a single product (>95%). This medium dependent product selectivity is attributed to conformational and translational restrictions enforced on the reactant as well as intermediates by the cyclodextrin cavity. 相似文献
13.
A series of eight N1-(β-D-ribofuranosyl)-C4-(coumarin-4′′-yl)-1,2,3-triazoles have been synthesized by Cu(I)-catalyzed click reaction of 1-azido-1-deoxy-2,3,5-tri-O-benzoyl-β-D-ribofuranose with differently substituted 4-ethynylcoumarins followed by debenzoylation of the resulted N1-(2′,3′,5′-tri-O-benzoyl-β-D-ribofuranosyl)-C4-(coumarin-4″-yl)-1,2,3-triazoles in 71 to 89% overall yields. The structures of all the synthesized compounds were established on the basis of their spectral data analysis that was further confirmed by X-ray data analysis of one of the model benzoylated compounds, i.e. N1-(2′,3′,5′-tri-O-benzoyl-β-D-ribofuranosyl)-C4-(7″-isopropoxycoumarin-4″-yl)-1,2,3-triazole. 相似文献
14.
In this paper, a nonlinear mathematical model is proposed and analyzed to study the depletion of dissolved oxygen caused by interactions of organic pollutants with bacteria in a water body, such as lake. The system is assumed to be governed by three dependent variables, namely, the cumulative concentration of organic pollutants, the density of bacteria and the concentration of dissolved oxygen. In the model, the coefficient of interaction of organic pollutants with bacteria depends upon the concentration of dissolved oxygen nonlinearly and explicitly, which is the main focus of this paper, has never been studied before. The stability theory of differential equations is used to analyze the model and to confirm the analytical results numerical simulation is performed. The model analysis shows that if the coefficient of interaction mentioned above depends upon dissolved oxygen explicitly, the decrease in its concentration is more than the case when the interaction does not depend on dissolved oxygen and consequently the depletion of organic pollutants is also more in such a case. 相似文献
15.
Smriti Singh Ilona Zilkowski Andrea Ewald Tobias Maurell‐Lopez Krystyna Albrecht Martin Möller Jürgen Groll 《Macromolecular bioscience》2013,13(4):470-482
Nanogels consist of three dimensionally cross‐linked hydrophilic polymer chains and can thus be easily modified through functionalization of the polymeric building blocks, for example to yield stimuli‐sensitive materials. For drug transport and intracellular release, redox‐sensitive systems are especially of interest, as the intracellular space is reductive. In this study, parameters that allow preparation of nanogels with tunable size between 150 and 350 nm are systematically evaluated and identified. Most importantly, a new and mild oxidation catalyst, alloxan, is introduced for the preparation of the nanogels. This broadens the range of possible payloads to more‐sensitive molecules. Particle stability, degradation in cytosolic conditions, and cytocompatibility in concentrations up to 10 mg · mL?1 are demonstrated.
16.
The problem of the creeping flow through a spherical droplet with a nonhomogenous porous layer in a spherical container has been studied analytically. Darcy’s model for the flow inside the porous annular region and the Stokes equation for the flow inside the spherical cavity and container are used to analyze the flow. The drag force is exerted on the porous spherical particles enclosing a cavity, and the hydrodynamic permeability of the spherical droplet with a non-homogeneous porous layer is ca... 相似文献
17.
Smriti Moi Shamasoddin Shekh K. Kasi Amarnath Reddy Pooja Dhurjad Rajesh Sonti Konkallu Hanumae Gowd 《Photochemistry and photobiology》2023,99(3):911-919
Photostabilizers have been used to impart stability to an FDA-approved chemical UV-A filter avobenzone against the UV-A radiations and sunlight. The thiol group of glutathione plays a critical role in imparting the photostabilization activity of glutathione on avobenzone. The current report aims to evaluate the photostabilization activity of multiple thiols containing cysteine peptides on avobenzone. Cysteine-tripeptide and cysteine-pentapeptide were chemically synthesized and characterized using mass spectrometry. Synthetic peptides were assessed for their photostabilization activity on the enolic-form of the avobenzone under natural sunlight using UV spectroscopy in both protic and aprotic solvents. Unlike glutathione, which has pronounced activity in protic solvents, cysteine-pentapeptide exhibits similar photoprotection activity in both protic and aprotic solvents. Computational calculations using DFT suggest that peptide cysteine thiols may assist in the reversal of the photoketonization process of avobenzone thereby exhibiting the photoprotection activity to the enolic-form of avobenzone. Peptide cysteine thiols lower the activation energy barrier of keto-to-enol tautomerization of avobenzone by 30 kcal mol−1 by assisting the proton shuttle through a six-membered transition state. The current report emphasizes the applications of peptide thiols in cosmetics and may help in the development of peptides as aesthetic medicines. 相似文献
18.
Dr. Fuat Topuz Dr. Smriti Singh Dr. Krystyna Albrecht Prof. Dr. Martin Möller Prof. Dr. Jürgen Groll 《Angewandte Chemie (International ed. in English)》2016,55(40):12210-12213
Polycyclic aromatic hydrocarbons (PAHs) are combustion‐related pollutants and are ubiquitous in the environment, including in sources of drinking water. Upon contact with DNA, stable PAH–DNA adducts form rapidly as the first step towards their toxic effects. In this work, we prepared hydrophilic DNA nanogels to exploit this generic complexation process as a biomimetic scavenging method. This approach relies on interaction between PAHs and the complete network that constitutes the water‐swollen nanogels, and is not restricted to interfacial adsorption. Up to 720 μg of PAH per gram of DNA nanogel are taken up, meaning that 1 mg of DNA nanogel is sufficient to purify a liter of water containing the critical PAH concentration for cancer risk (600 ng L?1). As a result of short diffusion pathways, PAH uptake is rapid, reaching 50 % loading after 15 minutes. Beyond PAHs, DNA nanogels may be useful for the generic detoxification of water containing genotoxins, since most known molecules that strongly associate with DNA are mutagenic. 相似文献
19.
Avishek Ghosh Tulasi Barik Smriti Dewangan Paresh Kumar Majhi Takahiro Sasamori Shaikh M. Mobin Santanab Giri Saurav Chatterjee 《应用有机金属化学》2019,33(4)
A novel solvent free synthetic method has been designed by using rice husk ash (RHA) as solid support for the selective functionalization of ferrocenyl derivatives and described the synthesis of a 1,1′‐unsymmetrically bi‐functionalized ferrocenyl compounds for their biological evaluation. Single crystal X‐ray structural evaluation showed some interesting intra‐molecular hydrogen bonding interactions across the chains of the ferrocenyl molecule, while DFT calculation revealed the significance of the orientation between the two cyclopentadienyl rings for the hydrogen bonding interaction. Redox and antibacterial properties have been studied to understand the electronic and biological effect of different hydrazone system and their potential for future application. 相似文献
20.
The generation of key drug metabolites for the purpose of their complete structural characterization, toxicity testing, as well as to serve as standards for quantitative studies, is a critical step in the pharmaceutical discovery and development cycle. Here, we utilized electrochemistry/mass spectrometry for the detection and subsequent generation of six phase I metabolites of simvastatin and lovastatin. Both simvastatin and lovastatin are widely used for the treatment of hypercholesterolemia. There are known drug–drug interaction issues of statin therapy, and it has been suggested that the oxidative metabolites may contribute to the cholesterol-lowering effect of both statins. Of the known phase I metabolites of simvastatin and lovastatin, none are commercially available, and chemical means for the synthesis of a very few of them have been previously reported. Here, we report that electrochemical oxidation of less than 1 mg each of simvastatin and lovastatin led to the generation of three oxidative metabolites of each parent to allow complete nuclear magnetic resonance characterization of all six metabolites. The yields obtained by the electrochemical approach were also compared with incubation of parent drug with commercially available bacterial mutant CYP102A1 enzymes, and it was found that the electrochemical approach gave higher yields than the enzymatic oxidations for the generation of most of the observed oxidative metabolites in this study. Figure
Generation of statin drug metabolites by EC/MS (representative mass voltammogram shown), and recombinant CYP enzymes 相似文献