Synthesis, Characterization, and Reactivity of Chelating Ligand Complexes of Group 13-15 Elements

2,6-bis(benzimidazol-2-yl)pyridine derivative (G-BZIMPY, G = NBn, N(3,5-CF3)Bn, N-allyl and O) have been used as pincer ligands to coordinate and isolate various group 13-15 complexes. For Group 13, treatment of G-BZIMPY with two equivalents of GaCl3 results in the self-ionization products [G-BZIMPYGaCl2][GaCl4]. This Ga(III) complex can be reduced to a Ga(I) centre using K2[Fe(CO)4] as a reducing agent to result in the Ga(I) complex [(NBn-BZIMPY)(Cl)Ga–Fe(CO)4] (Chapter 2). Group 14 complexes of G-BZIMPY have been synthesized in a similar fashion through the self-ionization reactions of G-BZIMPY with two equivalents of MCl2 (M = Ge, Sn) to yield [G-BZIMPYMCl][MCl3]. Attempts to reduce these complexes into the M(0) centre were not successful. Other reactivities and UV-vis studies are detailed in this dissertation (Chapter 3). Comparison of group 13 and 14 complexes of G-BZIMPY to complexes of the structurally similar bis(imino)pyridine (DIMPY) are studied and reveal G-BZIMPY as a stronger donor than DIMPY for group 13 coordination. For group 15 elements, treatment of PnCl3 (Pn = P, As, Sb) with G-BZIMPY does not yield any reactivity, however, the addition of TMS-OTf (Trimethylsilyl trifluoromethanesulfonate) results in the isolation of [G-BZIMPYPnCl][OTf]2 (Chapter 4). In-addition, a tetradentate ligand tris((1-ethyl-benzoimidazol-2-yl)methyl)amine (BIMEt3) has been investigated. A series of cationic complexes involving a pnictogen(III) (Pn = P, As, Sb) centre coordinated to BIMEt3 have been synthesized and comprehensively characterized. Oxidation of [P(BIMEt3)]3+ with XeF2 provides access to [PF2(BIMEt3)]3+ representing the first structurally characterized example of a phosphorus(V) centred trication (Chapter 5). Attempts to synthesize an anionic carbon(0) are detailed in chapter 6. Although obtaining an anionic carbon(0) was not successful, it lead to a series of interesting compounds and results. Compounds containing carbon centre behave differently than their heavier group-14 analogues of the same bidentate anionic bisphosphine ligand

Assessing the Quality of Whole Genome Alignments in Bacteria

Comparing genomes is an essential preliminary step to solve many problems in biology. Matching long similar segments between two genomes is a precondition for their evolutionary, genetic, and genome rearrangement analyses. Though various comparison methods have been developed in recent years, a quantitative assessment of their performance is lacking. Here, we describe two families of assessment measures whose purpose is to evaluate bacteria-oriented comparison tools. The first measure is based on how well the genome segmentation fits the gene annotation of the studied organisms; the second uses the number of segments created by the segmentation and the percentage of the two genomes that are conserved. The effectiveness of the two measures is demonstrated by applying them to the results of genome comparison tools obtained on 41 pairs of bacterial species. Despite the difference in the nature of the two types of measurements, both show consistent results, providing insights into the subtle differences between the mapping tools

Examining the Attitudes and Adoption Level of E-Learning Among UUM's International Postgraduate Students

Nowadays, many education institutious especially universities, have widened access to their courses through new methods of delivery, specifically via electronically mediated learning, or e-learning. Although online learning clearly has a growing presence in higher education, discussions about implementing e-learning continue to lack consensus. Universiti Utara Malaysia has established the use of e-learning system; however, the actual information of the e-learning implementation in Universiti Utara Malaysia remains unclear. It is imperative to evaluate the study and find out the postgraduate perspective on the e-learning implementation in the university itself. By investigating the international postgraduate experiences of those implementing e-learning, our aim is to inform on e-learning and to pick some of the reality of e-!earning environment university. Knowing exactly how international postgraduate students feel about educational technology will permit to manage the psychological aspects of the process and offer motives for the adoption and use of educational technology. In our study, we determined the type of applications students used in e-learning and the adoption levels of e-learning among the students. We also examined the international postgraduate attitudes towards e-learning and the relationships between attitudes and adoption. Four hundred and seventy one international postgraduate students participated in this study. A research survey was carried out in University Utara Malaysia (UUM) by using a questionnaire method to collect data. Our results were statistically analyzed with SPSS by using paired t-test. From our study, we found that the international postgraduate students at UUM Malaysia have been exposed to some parts of the features offered by UUM Online system. However, many students are still not making full use of the features offered by UUM e-learning system. It is advisable to conduct further studies in the future to determine the functionality of the UUM e-learning system and the methods to overcome these reasons

SPRAY DRIED LACTOSE BASED PRONIOSOMES AS STABLE PROVESICULAR DRUG DELIVERY CARRIERS: SCREENING, FORMULATION, AND PHYSICOCHEMICAL CHARACTERIZATION

Objective: In the present investigation efforts were considered to optimize the different conditions for the preparation of spray dried lactose based proniosomes. The aim of this research was to investigate the feasibility of proniosomes as stable precursors for the development of niosomes as oral drug delivery system for poorly water-soluble drugs. Methods: A total of twenty-eight plain proniosomal formulae were prepared with various surfactant-cholesterol loading ratios in each formula using spray dried lactose as a carrier. Span 20, 40, 60 and 80 were used in various molar ratios with cholesterol. Different evaluation techniques were performed to study the performance of the prepared proniosomes. The micromeritic properties of the prepared proniosomes were analyzed. The reconstituted niosomes were further evaluated for morphological characterization using transmission electron microscope (TEM), particle size analysis, zeta potential, and polydispersity index (PDI). Finally, selected proniosomal formulae were tested for stability study. Results: The proniosomal formulae prepared using span 40 and span 60 exhibited excellent flowability while those prepared with span 20 and span 80 showed poor flow properties. TEM photographs revealed that the vesicles were discrete, spherical without aggregation. The mean vesicle size of reconstituted niosomes was found to be in the range between (252.9±0.43–624.3±0.23 nm) with perfect PDI values (0.387±0.05–0.835±0.03). The negative values of zeta potential indicated that all prepared formulae were stabilized by electrostatic repulsion forces. Stability studies confirmed that proniosomes give a more stable system that could overcome the problems of standard niosomes. Formulae with the smallest particle size, higher surface charge values and best flow properties were selected to be loaded with poorly soluble drugs for further study. Conclusion: The obtained results offered evidence that spray-dried lactose based proniosomes are promising stable drug delivery carriers and ready to incorporate various poorly water-soluble drugs in order to improve their limited oral bioavailability

Effect of Blood Glucose Concentrations on the Development of Chronic Complications of Diabetes Mellitus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90229/1/j.1875-9114.1998.tb03927.x.pd

Assessment in mathematics: a study on teachers’ practices in times of pandemic

Lockdowns imposed by many countries on their populations at the beginning of the COVID-19 crisis forced teachers to adapt quickly and without adequate preparation to distance teaching. In this paper, we focus on one of the most formidable challenges that teachers faced during the lockdowns and even in the post-lockdown emergency period, namely, developing assessment that maintains the pedagogical continuity that educational institutions typically require. Based on the results of a previous study, focused on the analysis of answers to an open-ended questionnaire administered to a population of 700 teachers from France, Germany, Israel and Italy, a semi-structured interview series was designed and implemented by the authors of this paper with a small group of teachers. The transcripts of these interviews were analysed according to the interpretative phenomenological analysis methodology, with the aim of investigating teachers' own perspectives on the following: (a) the difficulties with which they had to contend, with respect to the question of assessment; (b) the techniques adopted to deal with these difficulties; and (c) the ways in which the lockdown experience could affect the future evolution of teachers' assessment practices. This analysis supported us in formulating hypotheses concerning the possible long-term effects of lockdown on modes of assessment in mathematics

The Intensity of Social Networks Group Use among the Students of Jordanian Universities

The paper investigates the intensity of (Social Networking Sites) SNSs use among the students of Jordanian universities. Four universities were involved in this study, while 727 undergraduate students respond to a questionnaire that measured their intensity of SNSs use. To answer research questions, the researchers used descriptive statistics, ANCOVA, Chi-Square, and T-test. The data analyses revealed significant differences among students' uses of SNSs. The variables consisted of university, faculty, gender, and year level. The study recommendation was the focus on integrating SNSs within learning management systems