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31.
Eugenol, the major constituent of clove oil, has been widely used for its anesthetic and analgesic action in dentistry. Eugenol exhibits pharmacological effects on almost all systems and our aim is to review the research work that has identified these pharmacological actions. Eugenol possesses significant antioxidant, anti-inflammatory and cardiovascular properties, in addition to analgesic and local anesthetic activity. The metabolism and pharmacokinetics of the compound in humans have been studied. Eugenol has also been used as a penetration enhancer. The compound is a very promising candidate for versatile applications, and the design of new drugs based on the pharmacological effects of eugenol could be beneficial. 相似文献
32.
Madhav S. Mane Ravi S. Balaskar Sandip N. Gavade Pramod N. Pabrekar Murlidhar S. Shingare Dhananjay V. Mane 《中国化学快报》2011,22(9):1039-1042
The regiospecific oxidation of alkyl group of both sterically hindered and unhindered aromatic amine to corresponding carbonyl compound was done in aq. medium by using DDQ. The optimized reaction protocol was found to be most simple, high yielding and novel method for oxidation of alkyl group of aromatic amine in to its carbonyl compound. 相似文献
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We present a theoretical study of the dynamics of the coupled system of Jiang, McFarland, Bergman, and Vakakis. It comprises
a harmonically excited linear subsystem weakly coupled to an essentially nonlinear oscillator. We explored the rich dynamics
exhibited by this coupled system by determining its periodic responses and their bifurcations. Not surprisingly, we found
a lot of interesting dynamics over a broad frequency range: cyclic-fold, Hopf, symmetry-breaking, and period-doubling bifurcations;
phase-locked motions; regions with multiple coexisting solutions; hysteresis; and chaos. We did not find any occurrence of
energy transfer via modulation (also known as zero-to-one internal resonance); theoretically, the possibility of its occurrence
was ruled out for systems with weak nonlinearity and damping. Finally, we investigated the ef fectiveness of the so-called
nonlinear energy sink (NES) in vibration attenuation of forced linear structures. We found that the NES results in an increase
in the vibration amplitude of the linear subsystem, especially when the damping is low, contrary to the claim made by Jiang
et al. Also, we did not find any indication of nonlinear energy pumping or localization of energy in the NES, away from the
directly forced linear subsystem, indicating that the NES is not ef fective for controlling the vibrations of forced linear
structures. 相似文献
36.
Nano titanium dioxide (nTiO2), generally considered to be toxicologically inert, is manufactured in large quantities and extensively applied in consumer products. The small size and large surface area endow them with an active group or intrinsic toxicity. Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of (bio) chemical applications. One of the great advantages of this technique is its ability to provide information on the concentration, structure and interaction of biochemical molecules in their microenvironments within intact cells and tissues, non-destructively. Zebrafish (Danio rerio), one of the most important vertebrate model organisms used in developmental biology, are increasingly used in biomedical research, particularly as a model of human disease. In the present work, an attempt is made to study the effect of titanium dioxide, both nano and bulk, on the microenvironment of the liver tissues of Zebrafish using FT-Raman spectroscopy. The results of the present study suggest that TiO2 exposure demonstrate a marked influence on the microenvironments of the liver tissues of Zebrafish. A shift to a higher wavenumber and an increase in the intensity of the band at ∼1087 cm−1 in the TiO2 exposed tissues suggest that some of the conformational changes resulting from the alkali recovery process takes place due to TiO2 exposure. The decreased intensity ratio (I3220/I3400) observed in the titanium-exposed tissues suggests a decreased water domain size, which could be interpreted in terms of weaker hydrogen-bonded molecular species of water in the TiO2 exposed tissues. The observed shift of COO− bands to higher frequencies shows the disruption of salt bridges as a result of a change in the oppositely charged partners and due to the enhanced random coil conformation. The variation in the intensity ratio of the tyrosyl doublet (I858/I825) indicates variation in the hydrogen bonding of the phenolic hydroxyl group due to TiO2 exposure. The results further suggest that the microenvironments are greatly altered due to titanium nano exposure when compared to titanium bulk. In conclusion, the results indicate that FT-Raman spectroscopy might be a useful tool for rapid assessment of nano particle biological interactions. 相似文献
37.
Background
The extent of similarity between consolidation and reconsolidation is not yet fully understood. One of the differences noted is that not every brain region involved in consolidation exhibits reconsolidation. In trace fear conditioning, the hippocampus and the medial prefrontal cortex (mPFC) are required for consolidation of long-term memory. We have previously demonstrated that trace fear memory is susceptible to infusion of the protein synthesis inhibitor anisomycin into the hippocampus following recall. In the present study, we examine whether protein synthesis inhibition in the mPFC following recall similarly results in the observation of reconsolidation of trace fear memory. 相似文献38.
39.
A new approach in transfer-function methods for solving a variety of control-theoretic problems is to work with fractional representations over the ring of stable or proper stable rational functions of various transfer matrices. The rings of stable and proper stable rational functions are well known to be Euclidean domains. These rings differ critically from the polynomial ring by the nonuniqueness of the remainders obtained. This major difficulty in extending the idea of polynomial models of Fuhrmann to the rings of stable and causal stable rational functions is circumvented by choosing a remainder in a special form. A natural realization theory is thus developed for matrix fraction representations of transfer-function matrices over these rings. As an application of the new theory developed, linear matrix equations (QX+RY=T and QX+YR=T) over the rings of stable and causal stable rational functions are reduced to finite sets of linear equations over the base field. 相似文献
40.
Pramod P. Khargonekar Tryphon T. Georgiou A. Bülent Özgüler 《Linear algebra and its applications》1983
We examine the concept of skew-primeness of polynomial matrices in terms of the associated polynomial model. It is shown that skew-primeness can be characterized in terms of the property of decomposition of a vector space relative to an endomorphism. This basic result is then applied to the special case of nonsingular polynomial matrices. We investigate the nonuniqueness of skew-complements of a skew-prime pair. It is shown that the space of equivalence classes of skew-complements is in bijective correspondence with a finite-dimensional linear space. Finally, the equivalence of the solutions to the problem of output regulation with internal stability obtained via geometric methods and via polynomial matrix techniques is shown explicitly. 相似文献