Metal chelation in separation science

The science o f transition metal chelation finds applicability in many analytical areas where the determination of agents which will chelate transition metal ions, or the determination of transition metal ions themselves, is desired. This thesis details the use of transition metal chelation in solving analytical problems encountered in the adhesives, fertiliser and biomedical laboratoiy. In the adhesives industry, transition metal ions in anaerobic adhesives can initiate the polymerisation process, resulting in premature setting o f products in their packaging. Addition o f a chelating agent such as ethylenediaminetetraacetic acid, however, renders the metal ion inactive with respect to its catalytic properties. A novel method was developed for the simultaneous determination o f the seven metal cations Cu(II), Pb(II), Ni(II), Zn(II), Co(II), Cd(H), and Mn(H), with limits o f detection as low as 30 ppb for certain metal ions. The method has been shown to give no response in the presence of excess EDTA This was achieved by the development o f a solid-phase extraction procedure, and separation on a dynamically coated Cjg reversed-phase highperformance liquid chromatography column. In the fertiliser industry, chelates are added to commercial fertilisers for the supply of micronutrients to plants. The determination of the iron chelates of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxy-2- ethylenediaminetriacetic acid (HEEDTA), ethylenediaminedi(o-hydroxy-phenylacetic) acid (EDDHA), and ethylenediaminedi(o-hydroxy-p-methylphenyl) acetic acid (EDDHMA), and the Cu, Zn and Mn chelates of EDTA was investigated. The ionpairing reagent tetrabutylammonium hydroxide, gave a separation of all iron chelates on a Chromspher C jg column using a solvent switching system. Cu-, Zn-, and MnEDTA were separated using the ion-pairing reagent tetradecyltrimethylammonium bromide. For the iron chelates both limit of determination and linear range studies, showed that the method is capable of analysing the concentration range found in commercial fertilisers. The capabilities of gel permeation chromatography for the separation and purification of the above chelates, was also investigated. Of the two gels Bio-Gel P2 and Fractogel HW-40 (S), Fractogel HW40 (S) gave the best separation o f FeEDDHA, FeEDDHMA, FeDTPA and FeHEEDTA. CuEDTA, ZnEDTA and MnEDTA were found to co-elute with FeDTPA. Capillary electrophoresis (CE) has become very important in the analysis o f peptides, as it is a highly powerful mechanism of separation, and can analyse nanoliter sample quantities. However, detection methods employing UV, spectrofluorimetry, radiolabelling and mass spectrometry have limited sensitivity. A copper-coated capillary was developed for the determination of peptides by CE with electrochemical detection. A simple washing procedure produces a copper-coated column which is stable for 12 hours. Under alkaline conditions, peptides complex with Cu(II) from the walls of the column to form Cu(II)-peptide complexes which are subsequently oxidised at a carbon fibre electrode to form copper(III)-peptides. The system was shown to be applicable for the analysis of small peptides (five amino acids),and protected peptides, for which typical detection limits were in the lx lO 'range

The principle of least effort within the hierarchy of linguistic preferences: external evidence from English

The thesis is an investigation of the principle of least effort (Zipf 1949 [1972]). The principle is simple (all effort should be least) and universal (it governs the totality of human behavior). Since the principle is also functional, the thesis adopts a functional theory of language as its theoretical framework, i.e. Natural Linguistics. The explanatory system of Natural Linguistics posits that higher principles govern preferences, which, in turn, manifest themselves as concrete, specific processes in a given language. Therefore, the thesis’ aim is to investigate the principle of least effort on the basis of external evidence from English. The investigation falls into the three following strands: the investigation of the principle itself, the investigation of its application in articulatory effort and the investigation of its application in phonological processes. The structure of the thesis reflects the division of its broad aims. The first part of the thesis presents its theoretical background (Chapter One and Chapter Two), the second part of the thesis deals with application of least effort in articulatory effort (Chapter Three and Chapter Four), whereas the third part discusses the principle of least effort in phonological processes (Chapter Five and Chapter Six). Chapter One serves as an introduction, examining various aspects of the principle of least effort such as its history, literature, operation and motivation. It overviews various names which denote least effort, explains the origins of the principle and reviews the literature devoted to the principle of least effort in a chronological order. The chapter also discusses the nature and operation of the principle, providing numerous examples of the principle at work. It emphasizes the universal character of the principle from the linguistic field (low-level phonetic processes and language universals) and the non-linguistic ones (physics, biology, psychology and cognitive sciences), proving that the principle governs human behavior and choices. Chapter Two provides the theoretical background of the thesis in terms of its theoretical framework and discusses the terms used in the thesis’ title, i.e. hierarchy and preference. It justifies the selection of Natural Linguistics as the thesis’ theoretical framework by outlining its major assumptions and demonstrating its explanatory power. As far as the concepts of hierarchy and preference are concerned, the chapter provides their definitions and reviews their various understandings via decision theories and linguistic preference-based theories. Since the thesis investigates the principle of least effort in language and speech, Chapter Three considers the articulatory aspect of effort. It reviews the notion of easy and difficult sounds and discusses the concept of articulatory effort, overviewing its literature as well as various understandings in a chronological fashion. The chapter also presents the concept of articulatory gestures within the framework of Articulatory Phonology. The thesis’ aim is to investigate the principle of least effort on the basis of external evidence, therefore Chapters Four and Six provide evidence in terms of three experiments, text message studies (Chapter Four) and phonological processes in English (Chapter Six). Chapter Four contains evidence for the principle of least effort in articulation on the basis of experiments. It describes the experiments in terms of their predictions and methodology. In particular, it discusses the adopted measure of effort established by means of the effort parameters as well as their status. The statistical methods of the experiments are also clarified. The chapter reports on the results of the experiments, presenting them in a graphical way and discusses their relation to the tested predictions. Chapter Four establishes a hierarchy of speakers’ preferences with reference to articulatory effort (Figures 30, 31). The thesis investigates the principle of least effort in phonological processes, thus Chapter Five is devoted to the discussion of phonological processes in Natural Phonology. The chapter explains the general nature and motivation of processes as well as the development of processes in child language. It also discusses the organization of processes in terms of their typology as well as the order in which processes apply. The chapter characterizes the semantic properties of processes and overviews Luschützky’s (1997) contribution to NP with respect to processes in terms of their typology and incorporation of articulatory gestures in the concept of a process. Chapter Six investigates phonological processes. In particular, it identifies the issues of lenition/fortition definition and process typology by presenting the current approaches to process definitions and their typology. Since the chapter concludes that no coherent definition of lenition/fortition exists, it develops alternative lenition/fortition definitions. The chapter also revises the typology of phonological processes under effort management, which is an extended version of the principle of least effort. Chapter Seven concludes the thesis with a list of the concepts discussed in the thesis, enumerates the proposals made by the thesis in discussing the concepts and presents some questions for future research which have emerged in the course of investigation. The chapter also specifies the extent to which the investigation of the principle of least effort is a meaningful contribution to phonology

COTTON PRODUCTION AND TRADE IN IGALALAND OF CENTRAL NIGERIA, 1900 – 1986

This study examines the history of cotton production and trade in Igalaland of Central Nigeria, 1900-1986. Cotton was a major crop in Igalaland particularly during the colonial period because of its use as raw material in British textile and allied industries. As a result of this, concerted efforts were made by the colonial state in collaboration with expatriate firms towards its development. These efforts manifested in the forms of enactment of Cotton Marketing Ordinances and establishment of facilitative measures like the construction of road and inland waterway networks to enhance easy transportation of cotton from the hinterland to ginnery for onward shipment to Britain. Furthermore, this study interrogates the historical patterns of transformation that occurred in the local Igala society as a result of the production and marketing of cotton from the early twentieth century upto 1986. The major findings of this study are multilayered. The study demonstrates how the industrial revolution in Britain spurred the quest for raw materials, in this case, cotton in Igala land. The study notes that in the bid to maintain steady supply of cotton, the colonial state established the British Cotton Growing Association (BCGA) in 1902 and by 1906, BCGA established a Ginnery at Lokoja and Igalaland was a major area in which the bulk of the cotton was obtained from. In addition, the BCGA had Licensed Buying Agents who ferreted the nooks and crannies of Igalaland with the bid to buying cotton and propagating the culture of cotton to the natives. Using the Vent for Surplus theory of Hyla Myint, this study further argues that the upsurge in cotton production in this area within the period under study was a result of the creation of institutional, legislative and facilitative measures designed and consolidated by the colonial state and imperial merchants companies coupled with favourable environment which supported the cultivation of cotton. Besides, this study demonstrates the precarious placement of Igala cotton peasant farmers within the gamut of colonial cotton export production. The local farmers were exploited and exposed to the vagaries of incessant price fluctuations in the international market. The imposition of taxation coupled with the manipulation of local agency especially the Native Authority by the expatriate merchants led to the exploitation of the natives. This study traces the tapestry of the transformation of the cotton industry during the turbulent years of First World War, World Economic Depression and the Inter war periods. Methodologically, both primary and secondary sources of historical data were adopted. The study concludes by asserting that enormous potentials and opportunities existed in the Igala cotton industry as a veritable tool for economic diversification and development.Production and trade of cotton in Igalaland

Volcanic architecture of the Deccan Traps, western Maharashtra, India: an integrated chemostratigraphic and paleomagnetic study

Detailed volcanostratigraphic logs of seven traverses up the lava sequence in the Western Ghats, Deccan Traps, India, are presented. The main study area, the Mahabaleshwar Plateau, was chosen because the lavas were emplaced around the time of the Cretaceous-Tertiary Boundary and because there is access to exposed lavas on three of its four sides, permitting investigation of the volcanic architecture in 3-D. Besides characteristics of the lava units, the logs include integrated geochemical and palaeomagnetic samples. The lava pile is dominated by pthoehoe sheet lobes and smaller lobes and toes. It can be divided into flow-fields, the products of one eruption, by the occurrence of weathering horizons. Palaeomagnetic results demonstrate that the chron 29R/29N reversal boundary horizon occurs in all four of the traverses around the Plateau and nearby Khumbarli Ghat. The elevation of the reversal horizon on each traverse varies between 897-945 m and 982 m, a value greater than that predicted by the small regional dip. Statistical analysis of geochemical data from samples taken between the reversal horizon and the base of the Mahabaleshwar Formation do not show any apparent correlation around the Mahabaleshwar Plateau, indicating that individual sheet lobes are less than 20 km wide. Determining the lateral extent of flow-fields is not possible using this method but from the occurrence of a similar number of flow-fields in three traverses of similar length round the Plateau, it is probable that most flow fields are at least as wide as the Mahabaleshwar Plateau (more than 20 km). Comparing the thickness of the lava pile between the base of the Mahabaleshwar Formation, the palaeomagnetic reversal horizon and the laterite cap, shows that as much as 95m of topography occurred on the surface of the active Deccan lavas over a distance of approximately 20 km. The volcanic architecture is controlled by the morphology of small sheet lobes, large sheet lobes, and, on a larger scale, flow-fields. These observations, and the varying number of individual sheet lobes making up flow-fields, demonstrates that the structure of the Deccan lava province at the level of eruptive units is extremely complex

Smoking cessation : a report of the Surgeon General

Tobacco smoking is the leading cause of preventable disease, disability, and death in the United States (U.S. Department of Health and Human Services [USDHHS] 2014). Smoking harms nearly every organ in the body and costs the United States billions of dollars in direct medical costs each year (USDHHS 2014). Although considerable progress has been made in reducing cigarette smoking since the first U.S. Surgeon General\u2019s report was released in 1964 (USDHHS 2014), in 2018, 13.7% of U.S. adults (34.2 million people) were still current cigarette smokers (Creamer et al. 2019). One of the main reasons smokers keep smoking is nicotine (USDHHS 1988). Nicotine, a drug found naturally in the tobacco plant, is highly addictive, as with such drugs as cocaine and heroin; acti- vates the brain\u2019s reward circuits; and reinforces repeated nicotine exposure (USDHHS 1988, 2010, 2014; National Institute on Drug Abuse [NIDA] 2018).The majority of cigarette smokers (68%) want to quit smoking completely (Babb et al. 2017). The 1990 Surgeon General\u2019s report, The Health Benefits of Smoking Cessation, was the last Surgeon General\u2019s report to focus on cur- rent research on smoking cessation and to predominantly review the health benefits of quitting smoking (USDHHS 1990). Because of limited data at that time, the 1990 report did not review the determinants, processes, or outcomes of attempts at smoking cessation. Pharmacotherapy for smoking cessation was not introduced until the 1980s. Additionally, behavioral and other counseling approaches were slow to develop and not widely available at the time of the 1990 report because few were covered under health insurance, and programs such as group counseling ses- sions were hard for smokers to access, even by those who were motivated to quit (Fiore et al. 1990).The purpose of this report is to update and expand the 1990 Surgeon General\u2019s report based on new scien- tific evidence about smoking cessation. Since 1990, the scientific literature has expanded greatly on the deter- minants and processes of smoking cessation, informing the development of interventions that promote cessa- tion and help smokers quit (Fiore et al. 2008; Schlam and Baker 2013). This knowledge and other major develop- ments have transformed the landscape of smoking ces- sation in the United States. This report summarizes this enhanced knowledge and specifically reviews patterns and trends of smoking cessation; biologic mechanisms; various health benefits; overall morbidity, mortality, and economic benefits; interventions; and strategies that pro- mote smoking cessation.Suggested citation: U.S. Department of Health and Human Services. Smoking Cessation. A Report of the Surgeon General. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health, 2020.2020-cessation-sgr-full-report.pdf2020713