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101.
Research on Chemical Intermediates - In the present study, the synthesis of ligand 6-chloro-5-7-dimethyl-4oxo-4H-chromene-3-carbaldehydes by three steps from the substituted phenol. The formed...  相似文献   
102.
This study investigated the effects of syringic acid (SA) on renal, cardiac, hepatic, and neuronal diabetic complications in streptozotocin-induced neonatal (nSTZ) diabetic rats. STZ (110 mg/kg i.p) was injected into Wistar rat neonates as a split dose (second and third postnatal day). Diabetes mellitus was diagnosed in adults by measuring fasting blood glucose levels, urine volume, and food and water intake. The treatment of SA (25 mg/kg, 50 mg/kg p.o) was given from the 8th to 18th postnatal week. To assess the development of diabetic complications and the effect of therapy, biochemical indicators in serum and behavioural parameters were recorded at specific intervals during the study period. SA (25 mg/kg, 50 mg/kg p.o) treatment reduced hyperglycaemia, polydipsia, polyphagia, polyuria, relative organ weight, cardiac hypertrophic indices, inflammatory markers, cell injury markers, glycated haemoglobin, histopathological score, and oxidative stress, and increased Na/K ATPase activity. These findings suggest that SA might significantly alleviate diabetic complications and/or renal, neuronal, cardiac, and hepatic damage in nSTZ diabetic rats.  相似文献   
103.
104.
Most simple magnesium salts tend to passivate the Mg metal surface too quickly to function as electrolytes for Mg batteries. In the present work, an electroactive salt [Mg(THF)6][AlCl4]2 was synthesized and structurally characterized. The Mg electrolyte based on this simple mononuclear salt showed a high Mg cycling efficiency, good anodic stability (2.5 V vs. Mg), and high ionic conductivity (8.5 mS cm?1). Magnesium/sulfur cells employing the as‐prepared electrolyte exhibited good cycling performance over 20 cycles in the range of 0.3–2.6 V, thus indicating an electrochemically reversible conversion of S to MgS without severe passivation of the Mg metal electrode surface.  相似文献   
105.
Biorobotic research continually demonstrates that behavior and cognition can be the emergent products of (1) embodied agents that are (2) dynamically embedded within an environment and (3) equipped with simple sensorimotor rules. Thigmotaxis is an orientation response to contact manifested in infant rats by wall following, corner burrowing, and group aggregation. Orientation responses have been long thought to be mediated only by sensory or central processes. Here we show that a random control architecture in a morphologically similar robot embedded in a scaled environment can reproduce thigmotaxic behaviors seen in infant rats. We conclude that (1) and (2) may play a larger role than previously thought in the generation of complex behaviors. © 2006 Wiley Periodicals, Inc. Complexity 12: 53–66, 2006  相似文献   
106.
The case of a particle moving along a nonsmooth constraint under the action of uniform gravity is presented as an example of indeterminancy in a classical situation. The indeterminacy arises from certain initial conditions having nonunique solutions and is due to the failure of the Lipschitz condition at the corresponding points in the phase space of the equation of motion.  相似文献   
107.
We demonstrate a kinetically-driven patterning scheme to selectively position arrays of Ge or Si nanoparticles within lithographically defined HfO2 windows. The surface reactions enabling patterning are revealed through temperature programmed desorption experiments and selectivity of the deposition is verified by X-ray photoelectron spectroscopy and scanning electron microscopy. Patterning is possible by exploiting the different reactivity of Ge and Si on HfO2 and SiO2 surfaces and employing a sacrificial SiO2 mask on which adatoms etch the SiO2 surface and do not accumulate to form nanocrystals.  相似文献   
108.
We study the problem of finding a point in the relative interior of the optimal face of a linear program. We prove that in the worst case such a point can be obtained in O(n 3 L) arithmetic operations. This complexity is the same as the complexity for solving a linear program. We also show how to find such a point in practice. We report and discuss computational results obtained for the linear programming problems in the NETLIB test set.Research supported in part by NSF Grant CCR-8810107, CCR-9019469 and a grant from GTE Laboratories.Research supported in part by NSF Grant DDM-8922636 and NSF Coop. Agr. No. CCR-8809615 through Rice University.  相似文献   
109.
A relaxed version of Karmarkar's method is developed. This method is proved to have the same polynomial time complexity as Karmarkar's method and its efficient implementation using inexact projections is discussed. Computational results obtained using a preliminary implementation of the method are presented which indicate that the method is practicable.This research was supported in part by NSF Grants CDR 84-21402 and DMS-85-12277 and ONR Contract N00014-87-K-0214.  相似文献   
110.
Fasicularin is a structurally novel thiocyanate-containing alkaloid isolated from the ascidian Nephteis fasicularis. Early biological experiments suggested that this compound's cytotoxic properties may stem from its ability to damage cellular DNA. Sequence gel analysis reveals that treatment of a 5'-32P-labeled DNA duplex with fasicularin in pH 7.0 buffer causes strand cleavage selectively at guanine residues. Further experiments indicate that production of these base-labile lesions in DNA involves alkylation of guanine residues by a fasicularin-derived aziridinium ion. This work reveals fasicularin as the first natural product found to generate a DNA-alkylating aziridinium ion via a mechanism analogous to the clinically used anticancer drugs mechlorethamine, melphalan, and chlorambucil.  相似文献   
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