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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Fusion of Spectral Reflectance and Derivative Information for Robust Hyperspectral Land Cover Classification

Kalluri, Hemanth Reddy 11 December 2009 (has links)
Developments in sensor technology have made high resolution hyperspectral remote sensing data available to the remote sensing analyst for ground cover classification and target recognition tasks. Further, with limited ground-truth data in many real-life operating scenarios, such hyperspectral classification systems often employ dimensionality reduction algorithms. In this thesis, the efficacy of spectral derivative features for hyperspectral analysis is studied. These studies are conducted within the context of both single and multiple classifier systems. Finally, a modification of existing classification techniques is proposed and tested on spectral reflectance and derivative features that adapts the classification systems to the characteristics of the dataset under consideration. Experimental results are reported with handheld, airborne and spaceborne hyperspectral data. Efficacy of the proposed approaches (using spectral derivatives and single or multiple classifiers) as quantified by the overall classification accuracy (expressed in percentage), is significantly greater than that of these systems when exploiting only reflectance information.
52

Organoiron approaches to stemodane derivatives

Fang, Xinqin January 1994 (has links)
No description available.
53

The Preparation of Pyridinium Derivatives by the Knoevenagel Condensation

Miller, Eugene James 05 1900 (has links)
An attempt is made in the work described in this paper to extend the series started by Hall and Platas by means of a Knoevenagel condensation between 3-hydroxy-1,4-naphtho-quinone-2-(4-methylpyridinium) anhydride and various aromatic aldehydes giving rise to a series of unsaturated substituents on the four position of the pyridine ring.
54

The oxidative-addition to some organosulfur compounds to bis (ð5-cyclopentadienyl) titanium (II) dicarbonyl /

Morris, Stephen Arthur January 1987 (has links)
No description available.
55

The oxidative-addition to some organosulfur compounds to bis (ð5-cyclopentadienyl) titanium (II) dicarbonyl /

Morris, Stephen Arthur January 1987 (has links)
Cp$ sb2$Ti(C))$ sb2$, where Cp = $ eta sp5$-cyclopentadienyl, reacted with RSSSR to give the catenated sulfur complexes Cp$ sb2$Ti(SR)(SSR), where R = CMe$ sb3$, CHMe$ sb2$, CH$ sb2$Ph, p-C$ sb6$H$ sb4$Me and CPh$ sb3$. These complexes, except for R = CPh$ sb3$, reacted with PhCH$ sb2$Br to give Cp$ sb2$TiBr$ sb2$, PhCH$ sb2$SR and PhCH$ sb2$SSR as major products. Cp$ sb2$Ti(SR)(SSR) desulfurized slowly in solution and rapidly in the presence of Ph$ sb3$P, giving Cp$ sb2$Ti(SR)$ sb2$ and Ph$ sb3$PS, in addition to other species. Similarly, phth-SSR, where phth = phthalimide, oxidatively added to Cp$ sb2$Ti(CO)$ sb2$ to give Cp$ sb2$Ti(X)(SSR), where X = phth and R = CMe$ sb3$, CHMe$ sb2$, CH$ sb2$Ph and p-C$ sb6$H$ sb4$Me. Solvolysis by MeOH and EtOH gave the species where X = OMe and OEt. In a similar manner Ph$ sb3$CSSCl added to Cp$ sb2$Ti(CO)$ sb2$ to give Cp$ sb2$Ti(Cl)(SSCPh$ sb3$). Treatment of Cp$ sb2$Ti(SR)(SSR) with (norbornadiene)Mo(CO)$ sb4$ gave the bridged dimers, (Cp$ sb2$Ti($ mu$-SR)-($ mu$-S$ sb{ rm x}$R)Mo(CO)$ sb4$), where x = 1 and 2 and R = CMe$ sb3$ and CHMe$ sb2$. The complexes where x = 2 contained the rare iso-$ mu$-$ eta sp1$-SSR ligand. In solution at low temperatures the bridging thiolato and disulfano groups were predominantly transoid. At higher temperatures, a dynamic process that allowed averaging of cyclopentadienyl ring environments took place. $ sp1$H NMR studies permitted evaluation of $ Delta{ rm G sbsp{c}{ ddagger}}$ for the averaging process.
56

Some Properties of Derivatives

Dibben, Philip W. January 1951 (has links)
This paper is concerned with certain properties of derivatives and some characterizations of linear point sets with derivatives. In 1946, Zygmunt Zahorski published a letter on this topic listing a number of theorems without proof, and no proof of these assertions has been published. Some of the theorems presented here are paraphrases of Zahorski's statements, developed in a slightly different order.
57

Derivatives of 1,4-Naphthoquinone and 1,4-Anthraquinone

Aboytes, Peter 08 1900 (has links)
The purpose of this investigation was the synthesis of some 1,4-naphthoquinones and 1,4-anthraquinones. It will be shown that some of these substituted quinones exhibit physiological properties.
58

Synthesis Of A Novel Family Of Amide Derivatives Of Podocarpic Acid

Nguyen, Dao 01 January 2004 (has links)
As a class, amides are of great interest in biological studies and pharmaceutical application. In this work, podocarpic acid, a natural tricyclic diterpene, derived from Podocarpus species, has been employed to form a novel family of amide derivatives which will later be studied for their potential as new drug leads. Novel amide derivatives of podocarpic acid were synthesized from podocarpic acid in three steps. The first step involved methylation with dimethylsulfate to form methyl-O-methylpodocarpate. This step was followed by iodination with iodine to give iodomethyl-O-methylpodocarpate. Finally amidation with various aliphatic amides using a copper catalyst yielded four amide derivatives of podocarpic acid. However, iodomethyl-O-methylpodocarpate did not react with aromatic amides. This is perhaps because of the reduction in electrophilicity of an aromatic amide versus an aliphatic amide. Thus this research had led to the discovery of a method that is selective for the synthesis of aliphatic amide derivatives of podocarpic acid. Furthermore, five novel derivatives of podocarpic acid have been synthesized. Therefore a small library of novel compounds has been synthesized by utilizing selective methodology, that are now available for future examination of their anticancer and anti-tuberculosis properties.
59

Preparation of new amino-, thio-, and sulfonyladamantane derivatives

Argyle, Joseph Craig 01 June 1970 (has links)
Various synthetic schemes were used to prepare a number of new amino-thio- and sulfonyladamantane compounds. By a nucleophilic substitution on 1-bromoadamantane, 1-(p-nitrophenylthio)adamantane was prepared from p-nitrothiophenol; the amino- and sulfonyl- derivatives of this compound were also prepared. Silver tosylate was used to generate the 1-adamantyl carbonium ion from 1-bromoadamantane in a synthetically useful procedure for preparing 1-adamantylamides from nitriles. Three 1-(1-adamantylcarbinyl)-2,5-dialkylpyrroles were prepared by Knorr-Paal reactions and reduced to the corresponding pyrrolidines. Thio- and aminomethyl 1-adamantyl ketones were prepared from methyl and bromomethyl 1-adamantyl ketones, respectively. Aliphatic and aromatic oxiranes were reacted with 1-aminoadamantane in a bomb at elevated temperatures to give several new 2-(1-adamantylamino)ethanol derivatives.
60

Evaluation of cryptolepine and huperzine derivatives as lead compounds towards new agents for the treatment of human African Trypanosomiasis.

Oluwafemi, A.J., Okanla, O., Camps, P., Muñoz-Torrero, D., Mackey, Z.B., Chiang, P.K., Seville, Scott, Wright, Colin W. January 2009 (has links)
No / The alkaloid cryptolepine (1) and eight synthetic analogues (2-8) were assessed for in vitro activities against Trypanosoma brucei. Four of the analogues were found to be highly potent with IC50 values of less than 3 nM and three of these were assessed against T. brucei brucei infection in rats. The most effective compound was 2,7-dibromocryptolepine (7); a single oral dose of 20 mg/Kg suppressed parasitaemia and increased the mean survival time to 13.6 days compared with 8.4 days for untreated controls. In addition, four huperzine derivatives (9-12) were shown to have in vitro antitrypanosomal activities with IC50 values from 303-377 nM.

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