Asymmetric reactions of organosilicon compounds and properties of novel optically active organosilanes

Partial reduction of racemic methoxysilanes by 1:1 complexes of lithium aluminium hydride with optically active cinchona and ephedra alkaloids give optically active silanes and methoxysilanes. Optical yields depend on the groups attached to silicon and the alkaloid used but in some cases approach 50%, The method has been used to prepare novel optically active organosilanes, possessing an asymmetric silicon centre, which are either inaccessible by any of the other available routes or would require a time consuming preparation. Such compounds are of use in the study of the mechanism of substitutions at silicon. Attempts have been made to rationalize the results of the asymmetric reductions in terms of differences in sterio and electronic interactions in diastereoisomeric transition states. Circular dichroism and optical rotatory dispersion spectra have been obtained for the optically active products in an attempt to elucidate the absolute configurations of the novel asymmetric organosilanes. The results from these studies provide a useful addition to the data so far accumulated for asymmetrically perturbed aromatic chromophores. Nuclear magnetic resonanoe studies of diastereoisomaric (-)-menthoxysilanes show that these compounds possess resonances extremely useful in the determination of optical purities for asymmetric organosilanes which possess an aromatic group. The effect of variable temperature on the spectra has revealed evidence for the conformational preferences in these compounds. Other diastereoisomeric alkoxysilanes have been prepared and their n.m.r.spectra studied in the hope of establishing trends. Exploratory studies for other asymmetric reactions proceeding at silicon have proved unfruitful.

Copper(II) complexes with unsymmetrical pentadentate ed3a-type diamino-tricarboxylate ligands. Crystal structures, configurational analysis and DFT study of complexes

The O–O–N–N–O-type pentadentate ligands H3ed3a, H3pd3a and H3pd3p (H3ed3a stands ethylenediamine-N,N,N′-triacetic acid; H3pd3a stands 1,3-propanediamine-N,N,N′-triacetic acid and H3pd3p stands 1,3-propanediamine-N,N,N′-tri-3-propionic acid) and the corresponding novel octahedral or square-planar/trigonal-bipyramidal copper(II) complexes have been prepared and characterized. H3ed3a, H3pd3a and H3pd3p ligands coordinate to copper(II) ion via five donor atoms (three deprotonated carboxylate atoms and two amine nitrogens) affording octahedral in case of ed3a3− and intermediate square-pyramidal/trigonal-bipyramidal structure in case of pd3a3− and pd3p3−. A six coordinate, octahedral geometry has been established crystallographically for the [Mg(H2O)6][Cu(ed3a)(H2O)]2 · 2H2O complex and five coordinate square-pyramidal for the [Mg(H2O)5Cu(pd3a)][Cu(pd3a)] · 2H2O. Structural data correlating similar chelate Cu(II) complexes have been used for the better understanding the pathway: octahedral → square-pyramidal ↔ trigonal- bipyramid geometry. An extensive configuration analysis is discussed in relation to information obtained for similar complexes. The infra-red and electronic absorption spectra of the complexes are discussed in comparison with related complexes of known geometries. Molecular mechanics and density functional theory (DFT) programs have been used to model the most stable geometric isomer yielding, at the same time, significant structural data. The results from density functional studies have been compared with X-ray data.

Using a systems approach in logistics design and planning

The international economic and business environment continues to develop at a rapid rate. Increasing interactions between economies, particularly between Europe and Asia, has raised many important issues regarding transport infrastructure, logistics and broader supply chain management. The potential exists to further stimulate trade provided that these issues are addressed in a logical and systematic manner. However, if this potential is to be realised in practice there is a need to re-evaluate current supply chain configurations. A mismatch currently exists between the technological capability and the supply chain or logistical reality. This mismatch has sharpened the focus on the need for robust approaches to supply chain re-engineering. Traditional approaches to business re-engineering have been based on manufacturing systems engineering and business process management. A recognition that all companies exist as part of bigger supply chains has fundamentally changed the focus of re-engineering. Inefficiencies anywhere in a supply chain result in the chain as a whole being unable to reach its true competitive potential. This reality, combined with the potentially radical impact on business and supply chain architectures of the technologies associated with electronic business, requires organisations to adopt innovative approaches to supply chain analysis and re-design. This paper introduces a systems approach to supply chain re-engineering which is aimed at addressing the challenges which the evolving business environment brings with it. The approach, which is based on work with a variety of both conventional and electronic supply chains, comprises underpinning principles, a methodology and guidelines on good working practice, as well as a suite of tools and techniques. The adoption of approaches such as that outlined in this paper helps to ensure that robust supply chains are designed and implemented in practice. This facilitates an integrated approach, with involvement of all key stakeholders throughout the design process.

Strategic development and physicochemical analysis of oral preparations for unstable drugs

Oral liquid formulations are ideal dosage forms for paediatric, geriatric and patient with dysphagia. Dysphagia is prominent among patients suffering from stroke, motor neurone disease, advanced Alzheimer’s and Parkinson’s disease. However oral liquid preparations are particularly difficult to formulate for hydrophobic and unstable drugs. Therefore current methods employed in solving this issue include the use of ‘specials’ or extemporaneous preparations. In order to challenge this, the government has encouraged research into the field of oral liquid formulations, with the EMEA and MHRA publishing list of drugs of interest. The current work investigates strategic formulation development and characterisation of select API’s (captopril, gliclazide, melatonin, L-arginine and lansoprazole), each with unique obstacles to overcome during solubilisation, stabilisation and when developing a palatable dosage from. By preparing a validated calibration protocol for each of the drug candidates, the oral liquid formulations were assessed for stability, according to the ICH guidelines along with thorough physiochemical characterisation. The results showed that pH and polarity of the solvent had the greatest influence on the extent of drug solubilisation, with inclusion of antioxidants and molecular steric hindrance influencing the extent of drug stability. Captopril, a hydrophilic ACE inhibitor (160 mg.mL-1), undergoes dimerisation with another captopril molecule. It was found that with the addition of EDTA and HP-β-CD, the drug molecule was stabilised and prevented from initiating a thiol induced first order free radical oxidation. The cyclodextrin provided further steric hindrance (1:1 molar ratio) resulting in complete reduction of the intensity of sulphur like smell associated with captopril. Palatability is a crucial factor in patient compliance, particularly when developing a dosage form targeted towards paediatrics. L-arginine is extremely bitter in solution (148.7 g.L-1). The addition of tartaric acid into the 100 mg.mL-1 formulation was sufficient to mask the bitterness associated with its guanidium ions. The hydrophobicity of gliclazide (55 mg.L-1) was strategically challenged using a binary system of a co-solvent and surfactant to reduce the polarity of the medium and ultimately increase the solubility of the drug. A second simpler method was developed using pH modification with L-arginine. Melatonin has two major obstacles in formulation: solubility (100 μg.mL-1) and photosensitivity, which were both overcome by lowering the dielectric constant of the medium and by reversibly binding the drug within the cyclodextrin cup (1:1 ratio). The cyclodextrin acts by preventing UV rays from reaching the drug molecule and initiated the degradation pathway. Lansoprazole is an acid labile drug that could only be delivered orally via a delivery vehicle. In oral liquid preparations this involved nanoparticulate vesicles. The extent of drug loading was found to be influenced by the type of polymer, concentration of polymer, and the molecular weight. All of the formulations achieved relatively long shelf-lives with good preservative efficacy.

Integrated and Personalized Digital Information Services

Digital information services are gradually becoming integrated with other systems and services such as library automation systems, student information services, and electronic learning systems. Users demand seamless access to a multitude of digital information services without leaving their desktop computers. They prefer using systems that recognize them when they log on, acknowledge their rights and privileges, and thus provide personalized information services. This paper summarizes the recent developments concerning integrated and personalized digital information services. It first emphasizes the role of the Internet in providing information services and then goes on to discuss the integration and personalization issues by emphasizing their importance for digital information services.

The Global Campus - ICT and the Future of Universities

This paper analyses the changes which the ICT causes on a global scale. The globalization of higher education triggered by e-Learning, the emergence of e-infrastructure for e-science, the Open Educational Resources movement, e-libraries and the tendency of building global educational alliances are analysed as well. Special emphasis is put on several wellknown university models, e.g. Research University, Open University and Entrepreneurial University, as well as on some emerging university models for the Knowledge Society, such as: Global University and Innovation University. The paper puts in focus the influence of the ICTs and the new organizational and business models they bring, such as Virtual University, eCampus, Enterprise 2.0, University 2.0. A new university model is defined—the Global Campus Model. Some arguments that the ultimate result of the ICTs driven transformations could turn the whole world into a Global Campus in the next few decades.

Modern Training Tools for Binding Design and Paper Conservation of Antique Books, Albums and Documents (BBINDING)

Report published in the Proceedings of the National Conference on "Education in the Information Society", Plovdiv, May, 2013

Digital Libraries as a Social Media

This paper presents an innovative approach for enhancing digital libraries functionalities. An innovative distributed architecture involving digital libraries for effective and efficient knowledge sharing was developed. In the frame of this architecture semantic services were implemented, offering multi language and multi culture support, adaptability and knowledge resources recommendation, based on the use of ontologies, metadata and user modeling. New methods for teacher education using digital libraries and knowledge sharing were developed. These new methods were successfully applied in more than 15 pilot experiments in seven European countries, with more than 3000 teachers trained.

Africa's World Cup:critical reflections on play, patriotism, spectatorship, and space

Africas World Cup: Critical Reflections on Play, Patriotism, Spectatorship, and Space focuses on a remarkable month in the modern history of Africa and in the global history of football. Peter Alegi and Chris Bolsmann are well-known experts on South African football, and they have assembled an impressive team of local and international journalists, academics, and football experts to reflect on the 2010 World Cup and its broader significance, its meanings, complexities, and contradictions. The World Cups sounds, sights, and aesthetics are explored, along with questions of patriotism, nationalism, and spectatorship in Africa and around the world. Experts on urban design and communities write on how the presence of the World Cup worked to refashion urban spaces and negotiate the local struggles in the hosting cities. The volume is richly illustrated by authors photographs, and the essays in this volume feature chronicles of match day experiences; travelogues; ethnographies of fan cultures; analyses of print, broadcast, and electronic media coverage of the tournament; reflections on the World Cups private and public spaces; football exhibits in South African museums; and critiques of the World Cups processes of inclusion and exclusion, as well as its political and economic legacies. The volume concludes with a forum on the World Cup, including Thabo Dladla, Director of Soccer at the University of KwaZulu-Natal, Mohlomi Kekeletso Maubane, a well-known Soweto-based writer and a soccer researcher, and Rodney Reiners, former professional footballer and current chief soccer writer for the Cape Argus newspaper in Cape Town. This collection will appeal to students, scholars, journalists, and fans. Cover illustration: South African fan blowing his vuvuzela at South Africa vs. France, Free State Stadium, Bloemfontein, June 22, 2010. Photo by Chris Bolsmann.

Readiness for school: A study of parent, teacher, and preschool provider perspectives

A possible gap exists between what parents and preschool providers know concerning children's readiness for school and what they should know when compared to teacher expectations. Students are experiencing difficulty in early schooling as a result of this gap in perspectives. This study's purpose was to describe, explain, and analyze the perspectives of parents, teachers, and preschool providers concerning school readiness. The qualitative strategy of interviewing was used with six parents, six teachers, and two preschool provider participants. Interview transcripts, field notes, member checking, and document analysis were used to interpret data and support findings. Categorization and coding organized data and aided in theory development. ^ Major findings of the study include: (a) All participant groups stress social skills, communication skills, and enthusiasm as most valuable for school readiness; (b) All participant groups agree parents have primary responsibility for readiness preparation; (c) Many participants suggest variables concerning family, economics, and home life contribute to a lack of readiness; (d) Parents place greater value on academic skills than teachers or preschool providers; (e) Preschool programs are identified as having the potential to significantly influence readiness; (f) Communicating, providing positive learning experiences, and providing preschool experience are valuable ways to prepare students for school, yet, differences were found in the types of experiences noted; (g) Participant perspectives indicate that informing parents of readiness expectations is of major importance, and they offer suggestions to accomplish this goal such as using public libraries and pediatrician offices as houses for written information and having kindergarten teachers make presentations at preschools. ^ This study concludes that parents and preschool providers do have knowledge concerning readiness for school. They may not, however, be in a position to carry out their responsibilities due to the intervening variables that inhibit the amount of time, interaction, and communication they have with the children in their care. This study discloses the beliefs of parents and preschool providers that children are ready for school, while teachers conclude that many children are not ready. Suggestions for readiness preparation and information dissemination are significant findings that offer implications for practice and future study. ^

Defining Moments: A Cuban Exile's Story about Discovery and the Search for a Better Future, Lecture by José I. Ramírez

This flyer promotes the event "Defining Moments: A Cuban Exile's Story about Discovery and the Search for a Better Future, Lecture by José I. Ramírez",sponsored by the FlU Libraries and the Cuban Research Institute.

Simulation and analysis of network traffic for efficient and reliable information transfer

With the growing commercial importance of the Internet and the development of new real-time, connection-oriented services like IP-telephony and electronic commerce resilience is becoming a key issue in the design of TP-based networks. Two emerging technologies, which can accomplish the task of efficient information transfer, are Multiprotocol Label Switching (MPLS) and Differentiated Services. A main benefit of MPLS is the ability to introduce traffic-engineering concepts due to its connection-oriented characteristic. With MPLS it is possible to assign different paths for packets through the network. Differentiated services divides traffic into different classes and treat them differently, especially when there is a shortage of network resources. In this thesis, a framework was proposed to integrate the above two technologies and its performance in providing load balancing and improving QoS was evaluated. Simulation and analysis of this framework demonstrated that the combination of MPLS and Differentiated services is a powerful tool for QoS provisioning in IP networks.

An alternative to BlackboardTM? Student use of web-based textbook teaching and learning material

This paper investigates the use of web-based textbook supplementary teaching and learning materials which include multiple choice test banks, animated demonstrations, simulations, quizzes and electronic versions of the text. To gauge their experience of the web-based material students were asked to score the main elements of the material in terms of usefulness. In general it was found that while the electronic text provides a flexible platform for presentation of material there is a need for continued monitoring of student use of this material as the literature suggests that digital viewing habits may mean there is little time spent in evaluating information, either for relevance, accuracy or authority. From a lecturer perspective these materials may provide an effective and efficient way of presenting teaching and learning materials to the students in a variety of multimedia formats, but at this stage do not overcome the need for a VLE such as Blackboard™.

Anodic behavior of InP: film growth, porous structures and current oscillations.

We review our recent work on the anodization of InP in KOH electrolytes. The anodic oxidation processes are shown to be remarkably different in different concentrations of KOH. Anodization in 2 - 5 mol dm-3 KOH electrolytes results in the formation of porous InP layers but, under similar conditions in a 1 mol dm-3 KOH, no porous structure is evident. Rather, the InP electrode is covered with a thin, compact surface film at lower potentials and, at higher potentials, a highly porous surface film is formed which cracks on drying. Anodization of electrodes in 2 - 5 mol dm-3 KOH results in the formation of porous InP under both potential sweep and constant potential conditions. The porosity is estimated at ~65%. A thin layer (~ 30 nm) close to the surface appears to be unmodified. It is observed that this dense, near-surface layer is penetrated by a low density of pores which appear to connected it to the electrolyte. Well-defined oscillations are observed when InP is anodized in both the KOH and (NH4)2S. The charge per cycle remains constant at 0.32 C cm-2 in (NH4)2S but increases linearly with potential in KOH. Although the characteristics of the oscillations in the two systems differ, both show reproducible and well-behaved values of charge per cycle.

Giant enhancement of n-type carrier mobility in highly strained germanium nanostructures

First-principles electronic structure methods are used to predict the rate of n-type carrier scattering due to phonons in highly-strained Ge. We show that strains achievable in nanoscale structures, where Ge becomes a direct bandgap semiconductor, cause the phonon-limited mobility to be enhanced by hundreds of times that of unstrained Ge, and over a thousand times that of Si. This makes highly tensile strained Ge a most promising material for the construction of channels in CMOS devices, as well as for Si-based photonic applications. Biaxial (001) strain achieves mobility enhancements of 100 to 1000 with strains over 2%. Low temperature mobility can be increased by even larger factors. Second order terms in the deformation potential of the Gamma valley are found to be important in this mobility enhancement. Although they are modified by shifts in the conduction band valleys, which are caused by carrier quantum confinement, these mobility enhancements persist in strained nanostructures down to sizes of 20 nm.