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1.
The structures of piperolein acids guineensine and wisanine have been confirmed by synthesis, UV irradiation of trans piperolein B acid ester gave the cis-isomer reported in the literature as the trans-isomer. The trans-2, trans-4 ethylenic bonds in guineensine and wisanine were introduced by reacting piperolein B aldehyde and 2-methoxy piperonal with the appropriate Wittig or Reformatsky reagent.  相似文献   
2.
The Shannon entropy (S) and the Fisher Information (I) entropies are investigated for a generalized hyperbolic potential in position and momentum spaces. First, the Schrodinger equation is solved exactly using the Nikiforov-Uvarov-Functional Analysis method to obtain the energy spectra and the corresponding wave function. By Fourier transforming the position space wave function, the corresponding momentum wave function was obtained for the low-lying states corresponding to the ground and first excited states. The positions and momentum of Shannon entropy and Fisher Information entropies were calculated numerically. Finally, the Bialynicki-Birula and Mycielski and the Stam-Cramer-Rao inequalities for the Shannon entropy and Fisher Information entropies, respectively, were tested and were found to be satisfied for all cases considered.  相似文献   
3.
Dominic A. Okorie 《Tetrahedron》1980,36(13):2005-2008
Three new alkaloids, polyavolensin, polyavolensinol and polyavolensinone, isolated from the stem of Polyathia suaveolens are shown to belong to a new class of indolosesquiterpenes with structures 4, 5, 6 respectively by PMR, CMR and mass spectrometry. They have also been interrelated by chemical reactions.  相似文献   
4.
Journal of Solid State Electrochemistry - Zinc sulphide thin films were deposited by chemical spray pyrolysis technique. The films were deposited at substrate temperatures of 300, 350 and...  相似文献   
5.
From Culcasia scandens P. Beauv., carota-4(5), 11(12)-diene (isodaucene), carota-3(4), 11(12)-dien-5-one, a new epoxide, 4,5-epoxy-carota-11(12)-ene (isodaucene epoxide) and beta-caryophyllene epoxide were isolated. The structures were established spectroscopically. Epoxidation of isodaucene with m-CPBA confirmed the structure and stereochemistry of the new epoxide.  相似文献   
6.
Hexane and dichloromethane extracts of Platostoma africanum P. Beauv., a plant popularly employed in Nigeria in the treatment of rheumatic symptoms, were evaluated for anti-inflammatory and antioxidant activities. Acute inflammatory effects were studied in the egg-albumin-induced rat paw edema. Both extracts produced significant (p < 0.05) and dose-dependent inhibition of the egg-albumin-induced pedal edema with the 400 mg kg(-1) dose being markedly better than piroxicam. The hexane and dichloromethane extracts also showed significant antioxidant activity with the dichloromethane extract exhibiting an IC(50) comparable to that of BHT, a synthetic antioxidant. Phytochemical investigation of the extracts afforded eight acidic pentacyclic triterpenes, namely, ursolic acid, oleanolic acid, epimaslinic acid, maslinic acid, corosolic acid, hyptadienic, euscaphic acid and tomentic acid, and a mixture of beta-sitosterol and stigmasterol. These constituents are reported for the first time in the genus.  相似文献   
7.
Alexander Okorie 《Talanta》2010,82(4):1421-2661
The optimization of a microwave dissolution procedure for potentially toxic elements in a contaminated soil sample has been evaluated using a central composite design approach. By considering the operating parameters of temperature, digestion time, microwave power and acid volume it was possible to identify the following optimum conditions: temperature, 160 °C; power, 750 W; digestion time, 25 min; and, an aqua regia volume of 13 mL. These microwave digestion conditions were then applied to 19 samples obtained from a former industrial site in Newcastle upon Tyne. Of the range of potentially toxic elements present at the site as a consequence of former industrial activity (As, Cd, Cr, Cu, Mo, Ni, Pb and Zn), the majority of topsoil samples indicated elevated concentrations of one or more of these elements. In particular, data obtained using either inductively coupled plasma mass spectrometry or flame atomic absorption spectroscopy indicates the high and wide concentration of Pb on the site (188-60300 mg/kg). Comparing the resulting potentially toxic elements data with UK soil guidelines values (SGVs) suggests at least parts of the site represent areas of potential human health risk. It was found that lead soil values exceeded the SGV on 17 out of the 19 sampling sites; similarly for As 6 out of 19 sampling sites exceeded the SGV. While for Cd, Cr and Ni the soil levels were below the stated SGVs.  相似文献   
8.
In this paper, Shannon entropy and Fisher information is studied for the screened Kratzer potential model and compared with the screened Coulomb in three dimensions. Our results showed similar higher-order characteristic behavior for position and momentum space. Our numerical results showed that increases in the accuracy of predicting particle location occurred in the position space. Our result shows that the sum of the position and momentum entropies satisfies the lower-bound Berkner, Bialynicki-Birula, and Mycieslki inequality. The Stam-Cramer-Rao inequalities relation for Fisher information and the expectation values were also satisfied for the different eigenstates.  相似文献   
9.
The structure of polyavolensin (4) has been determined by X-ray crystallography and the recently published structure needs revision.  相似文献   
10.
We discuss the thermodynamic properties of a modified Rosen-Morse potential using the $q$-deformed superstatistics approaches. We obtain the partition function with the help of the generalized Boltzmann factor from the modified Dirac delta distribution and uniform distribution. Other thermodynamic function is obtained for the superstatistics of the two distributions considered. We also discuss our results graphically and obtain the ordinary statistical quantities when the deformation parameter tends to zero.  相似文献   
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