SYNTHESIS AND CHARACTERISATION OF NOVEL BIOPOLYMERS VIA CLICK CHEMISTRY

The work throughout is the exploitation of copper catalysed Huisgen 1,3-dipolar azide–alkyne cycloaddition, as an efficient Click reaction, for the synthesis of novel biopolymers with a broad range of potential medical/industrial applications. The strategy is to develop a powerful tool for the synthesis of libraries of materials, which will be discussed in separate chapters. Chapter one is a general introduction on biopolymers and Click chemistry with emphasis on the related literature to the present work. Chapter two involves the application of Click chemistry on model compounds; 3-methyl benzyl alcohol and phenol. The resulting products were successfully prepared via Click chemistry. NMR spectroscopy was found to be a good choice for characterisation of the resulting products. Chapter three describes the application of Click chemistry on a disaccharide compound, α,α-D-trehalose. The di-azide functionalised trehalose was synthesised by tosylation followed by acetylation and subsequent reaction with sodium azide. Different functionalities such as ester, acrylate and epoxide groups were successfully introduced via Click chemistry. NMR and FT-IR spectroscopies were found to be efficient characterisation tools to follow up the Click modification reactions. The di-acrylate functionalised trehalose showed a great potential as a cross-linker in the free radical polymerisation of HEMA to generate hydrogels. Chapter four presents the utilisation of Click chemistry to produce trehalose-based glycopolymers which have a wide range of potential applications. Biodegradable glycopolymers containing PCL or PLA were synthesised via combination of ring opening polymerisation (ROP) and Click chemistry. The ROP of lactide and ε-caprolactone, using stannous octoate and propargyl alcohol, was carried out to synthesise alkyne end capped PLA and PCL which were then coupled with di-azide functionalised trehalose by Click reaction. NMR and IR were used to prove the structure of the materials. A new class of temperature responsive glycopolymers was also synthesised via copper wire catalysed Click-polymerisation of di-azide functionalised trehalose with di-alkyne terminated PEG. The cloud point of the aqueous solution of glycopolymer was evaluated and showed an LCST at ~39 oC, known as fever temperature. In addition, the phase transition was shown to be reversible. Chapter five involves the modification of 2-hydroxyethyl cellulose (HEC) via Click chemistry. For the first time, the azide functionalisation reaction of HEC was disclosed using a one pot reaction procedure. Neutral and ionic compositions of HEC were successfully synthesised by introducing different functionalities on HEC. The compositions containing carboxylic acid or 1ry amine functionalities can be treated in basic or acidic media to give polyelectrolytes based on HEC. The compositions containing both functionalities, carboxylic acid and 1ry amine, could produce polyampholytes. Sequential Click reactions were implemented to synthesise polydimethylsiloxane (PDMS) grafted HEC as well as potentially charged functionalities. These compositions are expected to receive a great interest in personal care and cosmetics applications. Mainly, solid state 13C-NMR and FT-IR spectroscopies were used to characterise these materials. Hydrophobically and hydrophilically modified HEC were also prepared by grafting PLA, PCL or PEG onto HEC using Click coupling reaction. AFM analysis showed that some exhibit a brushlike architecture. Chapter six describes the combination of Click chemistry and ROMP to synthesise various graft polymers. Two different grafting techniques; "grafting through" (the macromonomer approach) and "grafting onto" were involved in the synthesis. The "grafting through" method involved the synthesis of oxanorbornenyl di-PEG macromonomer by Click coupling of azide terminated PEG with di-alkyne functionalised oxanorbornene. The macromonomer was then subjected to ROMP to produce PEG grafted polyoxanorbornene. Polynorbornene-g-PCL and polynorbornene-g-PEG were prepared by "grafting onto" process. This was achieved by ROMP of bromide functionalised norbornene followed by reaction with sodium azide and then Click reaction with alkyne terminated PCL and PEG. The surface analysis of these graft polymers were studied using AFM. Random graft copolymer containing PEG and PCL side chains was also prepared by ROMP of a mixture of oxanorbornenyl di-PEG and bromide functionalised norbornene followed by reaction with sodium azide and then Click reaction with alkyne end capped PCL. Chapter seven entails general conclusions and suggestions for future work

Low complexity blind and data-aided IQ imbalance compensation methods for low-IF receivers

Low-IF and Zero-IF (direct conversion) down converters showed a great potential in implementing multi standard single chip solutions, eliminating the need to use off chip components and so reduce the area and the cost of the wireless receivers. One of the main performance limitations in the low-IF & Zero-IF down-converters is the components mismatch between the in-phase path and the quadrature-path named the IQ Imbalance (IQI) which limits the achievable image rejection ratio (IRR) of the down converters. Many techniques had been proposed to enhance the achievable IRR either by using calibration methods, e.g. using lab calibration, or by doing online compensation during signal reception. In this work those techniques are reviewed, proposing three new methods for blind IQI compensation techniques, the first proposed method targets the low input signal to interference ratio (low SIRin) while the second and third methods targets the moderate and high SIRin, showing that the proposed methods reach better performance and/or lower complexity than the methods already introduced in the literature. Also two techniques to perform data aided IQI compensation are introduced exploiting pilot symbols within the desired signal with no prior knowledge about the image signal. The first method exploits a preamble sequence assuming slow fading condition while the second approach exploits a sequence of pilots to compensate for the IQI being suitable for fast fading conditions as well. Simulation results showed that the proposed data aided techniques achieved shorter convergence time and higher image rejection ratio compared to the blind methods at high SNR values

Empowering professional syndicates in Egypt to achieve good governance; An application to the Egyptian Medical Syndicate

In searching for a governance reform strategy, the size, the vital roles of professional syndicates and their impact on the whole society place them among our top priorities. According to both the old and the new Egyptian constitutions, the professional syndicates have the legal base to represent the different professions, defend rights and interests of their members, improve the quality of the offered services to the society, and share in creating policies and procedures related to syndicates\u27 members and their careers. The discrepancy between the proposed role of the professional syndicates and the reality motivated this research into the reasons behind their weaknesses and poor performance. Little recent analysis of Egypt\u27s syndicates could be found in the literature. Selecting the Egyptian Medical Syndicate (EMS) as a case study was invoked by its vital role in health system reform. The main research question is “To what extent do the governance structure and procedures of the Egyptian Medical Syndicate correspond to international good governance standards? The qualitative method was adopted in this research. The aspects of the governance of the Canadian Medical Association (CMA) were used as a guide to highlight what components and core compositions of the structures of the EMS should be examined in the governance process and how? In addition, two questionnaires were developed. The first one conducted to the members and the later to senior managers and Board members. The respondents answered these questionnaires through group interview for members and Individual In-Depth Interview for senior managers and Board members. The aim was to make sure through these instruments, it will be possible to assess to what extent the EMS covered the standards principles of good governance and illuminate the areas which need to be improved. The study targeted doctors in three Egyptian governorates (Cairo, Giza and Gharbia) and the sample included males and females from different ages and backgrounds. The research found that the current governance system and procedures are in a bad need to be reformed to be consistent with international good governance standards. The findings of the study illustrated that there is a crucial need to issue a new law and bylaw for the Egyptian Medical Syndicate. The elections’ system needs to be revised. There is a necessity to identify a clear vision and mission for the EMS, setting the long term objectives, consider the annual planning and evaluation for the programs and activities. The Board of Directors needs to enhance its leadership and strategic planning skills. The study also highlighted the importance of considering the new tools of communications such as emails, website and video conferences to share information, and to achieve greater connection, participation and involvements for the members of the EMS. This study open the door to further research with hope to develop a good model to evaluate the governance system in other professional syndicates, and it will be possible to apply the model with some adaptation to fit the specific features of each syndicate

Synthesis of Anionic Surface Active Agents Containing Heterocyclic Moiety From Long Chain Fatty Alcohols

A series of novel groups of anionic surface active agent were synthesized. Synthesis of these surfactants via the reaction of long chain fatty alcohols (octyl, decyl and dodecyl) with maleic anhydride to give monoester. The monoester chloride reacted with amino derivatives of heterocyclic rings followed by addition of NaHSO3 .The surface tension, interfacial tension; Kraft point, emulsifying and wetting power were evaluated. Stability to hydrolysis, biodegradability and biological activities were measured. A comparison studies between the chemical structures and the results were done.  &nbsp

Modal Analysis of Prestressed Concrete Structural System for Wind Turbine Tower

The wind is almost seasoned and efficient of all renewable energies. The wind turbine tower (WTT) with a horizontal axis. It supported on steel, concrete, pre-stressed, hybrid, tower. As the turbine size grows up, the is heightened to generate spadesful of electricity power. The hybrid tower consists of pre-stressed concrete in the bottom and steel at the top. The parts of the steel tower have to be reasonably rigid, this design requirements raise the cost of a construction lifetime and decrease maintenance condition. To solve and improve this problem, a new proposed of the prestressed concrete (PC) structural system for the horizontal axis (WTT). The introducing tower is designed as an octagon section with internal ribs in the bottom along the hight of the tower with reducing in dimensions at different hight. The aerodynamic principle ware considered in optimizing the transverse profile of the tower. 100 m height of the tower system for the 3.6-megawatt turbine was designed using FE software (ANSYS)

Effects of chemical structure, solvent and solution pH on the visible spectra of some new methine cyanine dyes

Some new dimethine and bis-dimethine, cyanine dyes derived from benzo[2,3-b; 2`,3`-b`]bis-pyrazolo[4,5-b]-l,4-(oxa-, thia-, and pyra-)-zine-6,12-dione were synthesized. Effect of chemical structure on the electronic visible absorption spectra of all the synthesized cyanine dyes was investigated in 95% ethanol solution. Effects of solvent and/or solution pH on the electronic visible absorption spectra of some selected synthesized cyanine dyes were also examined in pure solvents having different polarities and/or in aqueous universal buffer solutions, respectively. Structural confirmations were carried out through elemental analysis, mass spectroscopy, IR and 1H NMR spectra

The Predictive Value of Vanin-1 in Pediatric Immune Thrombocytopenia

Background: Immune thrombocytopenia (ITP) has oxidative stress-related pathway as one of its possible mechanisms. Vanin-1 (VNN1) is an oxidative stress sensitive sensor. Objective: The present study was conducted to assess the clinical significance of VNN1 in pediatric ITP patients. Patients and Methods: A total of 50 kids with ITP have been involved in this work; 25 newly diagnosed, 25 chronic patients with ITP more than 12 months (15 responders and 10 non responders to treatment) and 25 apparently healthy children. All groups had their serum VNN-1 levels checked using a two-antibody sandwich enzyme-linked immunosorbent test. Results: The serum VNN1 level was significantly higher in ITP group than control group (p˂0.001). The level of serum VNN1 was significantly very high in newly diagnosed ITP group (p˂0.001) in comparison to chronic responders and chronic non responders ITP groups. Moreover, there was a significant increase in serum VNN1 level in chronic non responders ITP group (p˂0.001) compared to chronic responders group. In newly diagnosed ITP group, both age (r=-0.62, p=0.006) and the platelet count (r=-0.46, p=0.01) had a significant negative connection with serum VNN1 level. A cut-off value lower than 0.6 ng/ml for serum VNN1 could be used to distinguish the chronic non-responders ITP from chronic responders patients with 100 percent specificity and 90 percent sensitivity. Conclusion: From our current results, it is hypothesized that high VNN1 level plays a role in the pathogenesis and progress of pediatric ITP

Evaluation of a dual-T-type converter supplying an open-end winding induction machine

The multilevel inverter is a promising technology compared to two-level inverters in the applications of ac-drives and smart-grid applications. In this paper, a dual-T-type three-level inverters is used to drive an open-end winding induction machine. The Space-Vector Pulse-Width Modulation is selected as a good-performing control strategy to control the dual-inverter. Furthermore, an optimized method is used to select the proper switching state for the new configuration to decrease the converter losses. A comparison between the proposed configuration and the conventional diode clamped converter is made. The proposed drive system is designed and modelled by using Matlab/Simulink. It is shown that the converter can give the same hexagon, wave forms and harmonic spectrum of the five level converter. An optimized switching state selection is used to reduce the converter losses. The advantages and drawbacks of the dual-T-type configuration are discussed. In addition, the harmonic analysis and the loss calculations of the dual-T-type converter are provided and compared to the T-type three-level converter and the conventional five-level diode-clamped-converter