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Improvement of the thermodynamic description of polar molecules and their mixtures in the SAFT framework by Cripwell, Jamie Theo
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Page will reload when a filter is selected or excluded.- Nigeria 2 results 2
- Actor-merchants 1 results 1
- Computer Sciience 1 results 1
- Conjugated polymers 1 results 1
- Conjugated polymers which interact with biological systems have attracted interest due to their high conductivity, stability and electronic properties. Substituted polymers of 3-methyl pyrrole-4-carboxylic acid (MPCa) have been synthesised and used as components of biosensor, while unsubstituted polypyrroles are not effective for such application. However the mechanism of interaction, nature, the relative importance of dynamic and static electron correlation of the polymers are not completely understood. This research was designed using computational approach to study the molecular properties of substituted and unsubstittued pyrrole polymers with a view to understanding what make polymers of substituted pyrroles suitable components of biosensor. Structures of unsubstituted Pyrrole (Py); substituted pyrroles which include 3-methyl- pyrrole-4-carboxylic acid (MPCa), 3-methyl-pyrrole-4-carboxamide (MPCam), 3- methyl-pyrrole-4-sulfonic acid (MPSO3H), 3-methyl-pyrrole-1-carboxylic acid, (MPCb), 3-methyl-pyrrole-4-carbothioic acid (MPCOSH), 3-methyl-pyrrole-4- carbaldehyde (MPCHO) and their polymers were studied using quantum mechanical approach. The molecular properties investigated were Energy gap (Eg), Koopman’s reactivity descriptors, Fukui function, Lowest Unoccupied Molecular Orbital (LUMO), Highest Occupied Molecular Orbital (HOMO) and thermodynamic properties. These were calculated using restricted hybrid density functional theory with Becke three, Lee Yang and Parr at 6-31G(d) basis set. The calculated Eg were extrapolated to polymer through second order-degree polynomial equation. Spin-flip time density functional theory and coupled cluster single and double method with 6-311++G(d,p) basis set were used to calculate Coupled Cluster operator (T1) diagnostic and Vertical Singlet- Triplet (VST) gap to accurately determine polymers suitability as components of biosensor. All calculations were carried out using quantum mechanical software. The calculated Eg of the polymers decreased with increasing chain length and the nature of substituent. The order of Eg was MPCHO > Py > MPCb > MPCa > MPCam > MPSO3H > MPCOSH, with MPCOSH having the lowest value of 1.7 eV. Substituted polypyrroles except MPCHO have stronger electron-electron interactions since electron-electron interaction is more when the Eg is low (between 1.0 and 3.0 eV). Koopman’s reactivity descriptors were within the range of -3.9 to 2.4 eV (chemical i potential), 1.5 to 2.1 eV (chemical hardness) and 1.4 to 4.4 eV (electrophilicity index). Fukui function revealed a high electron density around the substituted functional groups and the LUMO and HOMO were extended over the C-C and C=C bonds. Thermodynamic parameters were enthalpy change (-4361.1 to -1045.7 kJmol-), entropy change (540.3 to 952.2 Jmol-1K-1) and free energy change (∆G0f) (-4361.2 to - 1045.8 kJmol-1) indicating spontaneous formation of the polymers. The T1 diagnostic of unsubstituted polypyrroles ranged from 0.0015 to 0.0013, while substituted polypyrroles ranged from 0.030 to 0.065. The T1 <0.02 indicated that unsubstituted polypyrrole had dynamic correlation with single reference (closed shell), while T1 >0.02 showed that substituted polypyrroles possessed static electron correlation with multireference (open shell) nature. The VST gap of unsubstituted polypyrroles ranged from 3.0 to 4.8 eV, while substituted polypyrroles ranged from 3.1 to 5.3 eV. The VST gap >0 revealed that all studied systems have a singlet ground state. The presence of substituents on polypyrrole decreased the energy gaps which led to the enhancement of their molecular properties making them suitable components of biosensor. 1 results 1
- Consumers 1 results 1
- Doctors in Training Healthcare Institutions 1 results 1
- Economic growth 1 results 1
- Educational Support Systems 1 results 1
- End-of-life utility 1 results 1
- Energy gap 1 results 1
- Game theory 1 results 1
- General 1 results 1
- Higher education is the climax of the process of providing knowledge, changing learners attitude and inculcating specialized skills in individuals preparatory to taking a life- long employment with intent to earning a living and equally contributing to national economic growth and development. The teaching and learning process is cardinal to the realization of the educational objectives of any nation. The advent of information and communication technology has made teaching and learning easier and beyond the traditional face to face interaction between the teacher and the learner. E-learning basically involving the transfer of skills and knowledge through an electronic device aims at improving the teacher/ learning process. In spite of the benefits of e-learning to both regular students distance learners, e-learning has been fraught with some challenges in Africa. Therefore, this paper discusses some of the challenges facing e-learning in Africa paarticularly in the Nigerian higher education system. These among others are epileptic power supply, high cost of procurement of computer hardware, inadequate infracture, and resistence to change on the part of the instructors, inability of learners to make use of ICT infracture, inadequate skilled manpower ICT, and corruption of computer storage device through viruses. Effectively managing the identified challenges means that the government would have to ensure regualr power supply, lecturers and learners should be trained in the use of ICT infrastructure, and the government should evolve viable ICT policy as well as control or subsidies the price of the ICT infrastructure to make it affordable for both lectures and learners. 1 results 1
- Imported Used Electronics (IUEs) are officially conceived in research oriented policy as potential and actual toxic “solid waste”, yet Nigeria remains a high consumer demand economy for them. IUEs include electronic monitors, digital devices, docking stations, cell phones, hand-held diagnostics, screening tools, television sets among others. Nigerian economy has evolved a socially constructed merchandise structure, which sustains IUEs trade. Literature, however limits IUEs discourses to pure-scientific framing of toxicology and dump in the Third World countries. This study, therefore, examined the subjective meanings that sustain the demand and merchandise of IUEs against official prohibition. Social action theory guided the study. The research design was exploratory. The qualitative research method was used. Data were generated from both primary and secondary sources. The research area was Lagos, and data were collected from Ikeja Computer Village, Westminster Used Electronics Market, Alaba International Market, Apapa Customs Office (ACO) and National Environmental Standards and Regulatory Enforcement Agency (NESREA). Participants were selected through purposive and snow-balling techniques. Non-participant observation for 15 months, In-depth Interviews (IDIs) were held with 22 IUE consumers and 22 market-actors. A total of 15 Key Informant Interviews (KIIs) were held with ACO officers (three), Association Heads of the three markets (eight) and veteran market actors (four). Six FGDs were conducted with IUEs consumers and market-actors, while five case studies were carried out on large scale consumers and market actors with at least 10 years working experience in IUEs merchandizing. Secondary data were sourced from NESREA and Basel Convention Coordinating Centre for Training and Technology Transfer for African Region, Ibadan. Data obtained were content analyzed. Demand for IUEs was hinged on peculiar social relations of consumption and merchandising which rationalized and constructed IUEs as desirable and affordable modern material objects. This relations involved processes of upgrading “solid waste” into tradable commodities infused with deluxe values and potentialities for leveling class. Artful transactions involved offer of disused electronics to market-actors in exchange for upgraded IUEs at a little token. A structure of interdependent actors sustained the IUEs merchandise. It included official gatekeepers such as Customs and NESREA, whose variable roles sustained entry of solid wastes into the market as IUEs; and administrators, merchants and interlinks-security who provided administrative, economic and coercive functions respectively. Furthermore, resuscitators upgrade otherwise wastes into merchandisable goods. Scavengers-collectors extract the irredeemable from merchants, to scrap-collectors who trade them to bulk-scrap-buyers. Bulk-buyers in turn, trade the scraps to domestic iron-smelting companies and/or illegally export them. In essence, IUEs remained tradable even in their end-of-life stages. Thus, local meanings of utility of IUEs and of employment potentialities were constructed against official policy perception of them as solid waste. Through a structured system of market interactions, actor-merchants contrived utility for Imported Used Electronics in the process of merchandise and consumption. Government should therefore accommodate local realities in order to proffer inclusive and robust IUEs policy. 1 results 1
- Imported used electronics 1 results 1
- Internet accessibility 1 results 1
- Library Educator 1 results 1
- Library Schools 1 results 1
- Political institutions 1 results 1
- Power transmission shafts, such as the crankshaft, impeller shaft, propeller-shafts, camshafts etc, are essential machine elements with wide application in mechanical systems. The manual shaft design procedure is known to be tedious and complex becajuse of large numbers of formulas, many computations and iteration procedures involved in the design. However, the use of Computer Aided Software (CAS) offers improved accuracy, high speed computations, reduced rigorousness and cumbersomeness involved in manual design procedure. This paper discusses the development of a Computer Aided Design and Drafuing (CADD) of power transmission shafts with multiple design criteria (strength, torsional rigidity, critical speed, Soderberg and lateral rigidity). Visual Basic 2008 was used for the implementation of the algorithm, while Fireworks was used for the development of the Graphical User Interface (GUI). The developed CADD is called UI-CADSHAFT. The software was applied for a typical case study and validated with manual design. Accurate results with increased productivity about twenty folds over the manual design are obtained. The software is fully interactive, user-friendly and runs stand-alone on Microsoft Windows. 1 results 1
- Substituted and unsubstituted polypyrrole 1 results 1
- Teaching 1 results 1
- The Internet is a global network of networks that enables computers of all kinds to directly and transparently communicate throughout the world. It is described as a global network and an 'Information Super-highway' (Computer Hope 2010). It is defined as a world-wide broadcasting capability, a mechanism for information dissemination, and a medium for collaboration and interaction between individuals and their computers without regard to geographical location (The Internet Society 2010). The internet is indeed a major technological breakthrough of our time. The Internet is a popular source of health information for health care providers and consumers. It has been recognized by many as an important mechanism for transforming medical care. The internet affords healthcare practitioners unprecedented access to huge volume, high quality, current and relevant health care information. Among currently available technologies only the Internet has the potential to deliver universal access to up-to-date health care information (Godlee, Pakenham-Wash et al. 2004). Accurate and up-to-date information is vital to maintain quality of health care. During the past decade, many health information resources have been developed and available online for use by health care professionals. The Internet has been used by healthcare professionals to obtain and share large amounts of medical information and to monitor diseases. The knowledge of the Internet as an important health information resource for physicians have greatly improved during the past decade as a result of patterns of use and medical impact measures (Bennett, Casebeer et al. 2004 ). The Internet has enabled health care practitioners to obtain and share health information and to track and monitor diseases (Centre for Disease Control 2003). In addition, it has made it easy and possible for physicians throughout the world to collaborate, communicate, and interact with each other (Manhas 2008). The Internet has brought about flexible communication between patients and doctors by empowering patients with information. It has also revolutionized the compilation, assessment and distribution of information relating to healthcare (Slattery 2008). In the last two decades, there has been a tremendous increase in the volume of healthcare information published online. The amount of online health information available to users keep growing on daily basis than can ever be imagined ten years back. A great variety of information resources are now available and accessible online. These include among others search engines (Google, Yahoo, Alta Vista, Lycos, Mama, etc) databases (MEDLINE/PubMed, Scopus, Web of Knowledge, EMBASE, African Index Medicus), portals, gateways, digital archives, libraries and institutional repositories. Recent, reliable, quality and up-to-date healthcare information are also available in websites of academic and health institutions, professional associations, governmental and non-governmental organizations. In addition, some governmental and not-for-profit organizations such as the National Institutes of Health (NIH) and Bioline International have digital archives for free full-text articles. Also available online are medical dictionaries, encyclopedias, abstracts and indexes, bibliographies, atlases, videos and drug information sources. Many of these information resources that provide accurate and reliable health care information for medical doctors are results of increase in the pace of healthcare research (Mckibbon, Fridsma et al. 2007) Information is worthless if it is not used. Availability of information is one thing, access to and use of the available information is another (Odutola 2003). According to Dervin and Nilan, “information use” is a process whereby the user tries to make sense of discontinuous reality in a series of information use behavior (Dervin and Nilan 2003). Systems that are not utilized do not result in expected efficiency and effectiveness gains (Agarwal and Prasad 1999). Availability of eresources has changed what users actually read and use; they tend to use what is easily accessible (Renwick 2005). The use of information varies among individuals, and professionals depending on their information needs and status. An important consideration in the process of health information gathering is accessibility and use of such information. 1 results 1
- The importance of economic and political institutions to economic growth has been demonstrated in the literature. However, little is known on how such institutions impact on growth and what determine the quality of economic institutions in Africa. Therefore, this study was aimed at examining the impact of economic and political institutions on growth as well as the impact of political transition on the quality of economic institutions. Game theory was used to develop a political economy model that incorporated institutional variables into the neoclassical Solow growth model. This model described the interactions among political power (de-jure and de-facto powers), institutions and economic growth. The model was empirically tested using data drawn from 29 African countries covering the period 1996 to 2009. The selection of countries was guided by availability of data and they spread across the continent. Indexes of economic and political institutions were computed from the World Bank’s governance indicators and the Polity IV database. The Ordinary Least Squares (OLS), fixed effect and Generalized Methods of Moments (GMM) techniques were used to test the impact of economic and political institutions on economic growth. A treatment analysis was also employed to test the impact of political transition on the quality of economic institutions and growth. Strong economic and political institutions had significant and positive impacts on economic growth. Countries with higher institutional qualities are found to be growing faster while those with lower quality grow slower. Generally, a 1.00% increase in the indexes of economic and political institutions led to 0.44% and 0.55% increase in economic growth respectively. However, the impacts of the two indexes differed across different sub-regions. The impact of economic institutions on growth was highest in the Southern African countries with a coefficient of 0.78% and lowest in West Africa with a coefficient of 0.20%. An increase in the index of political institution had the highest impact in the Central African countries and lowest in North Africa. Specifically, political institution was found to aid growth in Central Africa by 1.19% while it slowed down growth in North Africa by 0.49%. Countries that transited to democracy recorded 1.28% improvement in their quality of economic institutions and they grew about 0.51% faster than their pre-transition era. However, for countries where political elites persisted in power after the transition, the quality of economic institutions declined by 1.10% and they experienced a lower growth rate of 0.16%. Improvement in the quality economic institutions promote growth. Competitiveness of political system improved the quality of economic institutions and growth, while elites’ persistence in power reduced the two. Economic growth in Africa can be improved by building and strengthening institutions as well as promoting competitive democracy. 1 results 1
- This study computationally screened three key compounds (vanillin (VAN), oxophoebine (OPB), and dihydrochalcone (DHC)) derived from Xylopia aethiopica (Guinea pepper), a medicinal plant with known antiviral activity, against key druggable measles virus (MV) proteins (fusion protein (FUP), haemagglutinin protein (HMG), and phosphoprotein (PSP)). Each molecular species was subjected to a 100 ns molecular dynamics (MD) simulation following docking, and a range of postdynamic parameters including free binding energy and pharmacokinetic properties were determined. The docking scores of the resulting OPB-FUP (-5.4kcal/mol), OPB-HMG (-8.1 kcal/mol), and OPB-PSP (-8.0kcal/mol) complexes were consistent with their respective binding energy values (-25.37, -28.74, and -40.68 kcal/mol), and higher than that of the reference standard, ribavirin (RBV) in each case. Furthermore, all the investigated compounds were thermodynamically compact and stable, especially HMG of MV, and this observation could be attributed to the resulting intermolecular interactions in each system. Overall, OPB may possess inhibitory properties against MV glycoproteins (FUP and HMG) and PSP that play important roles in the replication of MV and measles pathogenesis. While OPB could serve as a scaffold for the development of novel MV fusion and entry inhibitors, further in vitro and in vivo evaluation is highly recommended. 1 results 1
- This work is a review of the different types of Educational Support Systems (ESS) useful for teaching and the various ways they can be applied for teaching. Rationales for the use of ESS for teaching in the university-based library schools in Nigeria were provided while literature relevant to the study were reviewed to relate past research studies, opinions and thoughts to the discussion. An exposition was done on the importance and benefits of these resources when applied to teaching in the library schools. Finally, the author concluded that the selection and acquisition of software and related activities will demand a high level of computer, digital and information literacies from the educators and it may require their learning and understanding, once and again, the principles of courseware design and the relevance of different applications to the instructional task at hand, in order to shift the paradigm to ESS-enabled dynamic and interactive teaching and learning environment where there will be excitement, individuality and yet collaboration. 1 results 1
- Universities 1 results 1
- Use of ESS 1 results 1
- Use of Online Health Information Resources 1 results 1
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