New approaches to antimalarial chemotherapy: design and synthesis of bicyclic endoperoxides and of peptide and peptidomimetic carbonyl containing cysteine protease inhibitors

Tese dout., Química Orgânica, Universidade do Algarve, 2007

Design and Synthesis of Conjugated Polymers for Photovoltaic and Chemosensor Applications

Department of Applied Chemistry, Cochin University of Science and Technology

Design and synthesis of efficient mac architectures for high speed decimal processor

Most of the commercial and financial data are stored in decimal fonn. Recently, support for decimal arithmetic has received increased attention due to the growing importance in financial analysis, banking, tax calculation, currency conversion, insurance, telephone billing and accounting. Performing decimal arithmetic with systems that do not support decimal computations may give a result with representation error, conversion error, and/or rounding error. In this world of precision, such errors are no more tolerable. The errors can be eliminated and better accuracy can be achieved if decimal computations are done using Decimal Floating Point (DFP) units. But the floating-point arithmetic units in today's general-purpose microprocessors are based on the binary number system, and the decimal computations are done using binary arithmetic. Only few common decimal numbers can be exactly represented in Binary Floating Point (BF P). ln many; cases, the law requires that results generated from financial calculations performed on a computer should exactly match with manual calculations. Currently many applications involving fractional decimal data perform decimal computations either in software or with a combination of software and hardware. The performance can be dramatically improved by complete hardware DFP units and this leads to the design of processors that include DF P hardware.VLSI implementations using same modular building blocks can decrease system design and manufacturing cost. A multiplexer realization is a natural choice from the viewpoint of cost and speed.This thesis focuses on the design and synthesis of efficient decimal MAC (Multiply ACeumulate) architecture for high speed decimal processors based on IEEE Standard for Floating-point Arithmetic (IEEE 754-2008). The research goal is to design and synthesize deeimal'MAC architectures to achieve higher performance.Efficient design methods and architectures are developed for a high performance DFP MAC unit as part of this research.

Theoretical Design and Synthesis of Donor-Acceptor Conjugated Polymers for Photovoltaic and NLO Applications

Polymers with conjugated π-electron backbone display unusual electronic properties such as low energy optical transition, low ionization potentials, and high electron affinities. The properties that make these materials attractive include a wide range of electrical conductivity, mechanical flexibility and thermal stability. Some of the potential applications of these conjugated polymers are in sensors, solar cells, field effect transistors, field emission and electrochromic displays, supercapacitors and energy storage. With recent advances in the stability of conjugated polymer materials, and improved control of properties, a growing number of applications are currently being explored. Some of the important applications of conducting polymers include: they are used in electrostatic materials, conducting adhesives, shielding against electromagnetic interference (EMI), artificial nerves, aircraft structures, diodes, and transistors.

Automatic Analysis and Synthesis of Controllers for Dynamical Systems Based On P

I present a novel design methodology for the synthesis of automatic controllers, together with a computational environment---the Control Engineer's Workbench---integrating a suite of programs that automatically analyze and design controllers for high-performance, global control of nonlinear systems. This work demonstrates that difficult control synthesis tasks can be automated, using programs that actively exploit and efficiently represent knowledge of nonlinear dynamics and phase space and effectively use the representation to guide and perform the control design. The Control Engineer's Workbench combines powerful numerical and symbolic computations with artificial intelligence reasoning techniques. As a demonstration, the Workbench automatically designed a high-quality maglev controller that outperforms a previous linear design by a factor of 20.

Design and synthesis of short antimicrobial peptides for plant protection. Study of their mode of action

Aquesta tesi doctoral està basada en el desenvolupament de nous agents antimicrobians derivats del pèptid híbrid cecropina A-melitina WKLFKKILKVL-NH2 (Pep3) que siguin sostenibles i útils per al control de malalties de plantes. Es van dissenyar i sintetitzar més de 133 anàlegs de Pep3 mitjançant química combinatòria. Es van obtenir anàlegs de Pep3 amb una elevada activitat contra fitopatògens i que presentaven baixa toxicitat. Els millors anàlegs van presentar eficàcies comparables amb pesticides de referència en la prevenció d'infeccions causades per fitopatògens. Es va estudiar el mecanisme d'acció de KKLFKKILKYL-NH2 (BP100) investigant la seva interacció amb models de membrana mitjançant tècniques espectroscòpiques. Es va observar la capacitat de BP100 a induir la permeabilització, la neutralització, i l'agregació de vesícules lipídiques aniòniques a una determinada concentració llindar. Es va deduir una equació que relaciona la CMI d'un pèptid antimicrobià amb la constant de partició i la concentració llindar en la membrana.

Expression of four beta-galactosidases from Bifidobacterium bifidum NCIMB41171 and their contribution on the hydrolysis and synthesis of galactooligosaccharides

This paper deals with two aspects tightly related to the enzymatic characteristics and expression of four beta-galactosidases (BbgI, BbgII, BbgIII and BbgIV) from Bifidobacterium bifidum NCIMB41171. The growth patterns of this strain indicated a preference towards complex (i.e. lactose, galactooligosaccharides (GOSs)) rather than simple carbohydrates (i.e. glucose and galactose) and a collaborative action and synergistic relation of more than one beta-galactosidase isoenzyme for either lactose or GOS hydrolysis and subsequent assimilation. Native polyacrylamide gel electrophoresis analysis of protein extracts from cells growing on different carbohydrates (i.e. glucose, lactose or GOS) indicated that two lactose hydrolysing enzymes (BbgI and BbgIII) and one GOS hydrolysing enzyme (BbgII) were constitutively expressed, whereas a fourth lactose hydrolysing enzyme (BbgIV) was induced in the presence of lactose or different GOS fractions. Furthermore, the beta-galactosidase expression profiles of B. bifidum cells and the transgalactosylating properties of each individual isoenzyme, with lactose as substrate, clearly indicated that mainly three isoenzymes (BbgI, BbgIII and BbgIV) are implicated in GOS synthesis when whole B. bifidum cells are utilised. Two of the isoenzymes (BbgI and BbgIV) proved to have better transgalactosylating properties giving yields ranging from 42% to 47% whereas the rest (BbgI and BbgIII) showed lower yields (15% and 29%, respectively).

Uncertainty in climate change impacts on basin-scale freshwater resources – preface to the special issue: the QUEST-GSI methodology and synthesis of results

This paper presents a preface to this Special Issue on the results of the QUEST-GSI (Global Scale Impacts) project on climate change impacts on catchment-scale water resources. A detailed description of the unified methodology, subsequently used in all studies in this issue, is provided. The project method involved running simulations of catchment-scale hydrology using a unified set of past and future climate scenarios, to enable a consistent analysis of the climate impacts around the globe. These scenarios include "policy-relevant" prescribed warming scenarios. This is followed by a synthesis of the key findings. Overall, the studies indicate that in most basins the models project substantial changes to river flow, beyond that observed in the historical record, but that in many cases there is considerable uncertainty in the magnitude and sign of the projected changes. The implications of this for adaptation activities are discussed.

Design and synthesis of peptides from bacterial ParE toxin as inhibitors of topoisomerases

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoluminescence properties and synthesis of a PZT mesostructure obtained by the microwave-assisted hydrothermal method

Micro-cube-shaped lead zirconate titanate was synthesized using the microwave-assisted hydrothermal method. Photoluminescence and field emission scanning electron microscopy were used for monitoring the formation of mesocrystals. Based on these results, a growth mechanism was then proposed which involved nanoparticle aggregation, nanoplate self-assembly on specific architecture and the final formation of mesoscopic micro-cube-shaped lead zirconate titanate. (C) 2011 Elsevier B. V. All rights reserved.

REGULATION OF BOVINE ENDOMETRIAL SECRETION OF PROSTAGLANDINS AND SYNTHESIS OF 2',5'-OLIGOADENYLATE SYNTHETASE BY INTERFERON-ALPHA MOLECULES

Experiments were performed to (1) verify the inhibitory effect of bovine trophoblast protein-1 (bTP-1) on uterine prostaglandin synthesis, (2) evaluate whether other interferon-alpha (IFN-alpha) molecules also inhibit prostaglandin secretion, and (3) test whether the enzyme 2',5'-oligoadenylate synthetase (2-5A synthetase) can be induced in endometrium by interferon-alpha. In experiment 1, all interferon molecules (bTP-1, oTP-1, bIFN-alpha and hIFN-alpha) equally inhibited secretion of PGF and PGE2 from endometrial explant cultures obtained at day 17 of the estrous cycle. In experiment 2, endometrial explants obtained from day 17 of the cycle were cultured with and without bovine serum albumin (BSA; 50-mu-g/ml) and bIFN-alpha (0, 0.84, 4.2, and 42 nM). Addition of BSA to the culture medium greatly enhanced the accumulation of PGF into the medium. The bIFN-alpha inhibited accumulation of PGF and PGE2 in both the presence or absence of BSA by 12 h. All three concentrations of bIFN-alpha were equally effective in inhibiting prostaglandin accumulation. Additionally, all concentrations of bIFN-alpha increased the amounts of 2-5A synthetase in endometrium. In conclusion, these results confirm the inhibitory effect of bTP-1 on PGF release from endometrium and demonstrate that bTP-1 can also inhibit PGE2 secretion. Furthermore, other interferon-alpha molecules, including bIFN-alpha, hIFN-alpha, and oTP-1, also reduced PGF and PGE2 secretion in culture. It is likely, therefore, that conceptus and other interferon-alpha molecules exert similar effects on endometrium in vitro and that the antiluteolytic effects of bIFN-alpha in vivo are mediated in part by changes in endometrial prostaglandin synthesis.

Design and synthesis of a new coumarin-based 'turn-on' fluorescent probe selective for Cu+2

The novel coumarin-based 'turn-on' fluorescent probe (E)-3-(2,5-dimethoxybenzylideneamino)-7-hydroxy-2H-chromen-2-one (MGM) was designed, synthesized, and characterized. This compound shows high selectivity for Cu+2, combined with a large fluorescence enhancement upon binding to Cu2+. Benesi-Hildebrand and Job plots demonstrate that the stoichiometry of the Cu+2 complex formed is 2:1. Preliminary studies employing epifluorescence microscopy demonstrated that Cu+2 could be imaged in human neuroblastoma SH-SY5Y cells treated with MGM. (c) 2012 Elsevier Ltd. All rights reserved.