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Some chemistry of orthomanganated ketones
(The University of Waikato, 1986) Gommans, Louis H. P.; Main, Lyndsay; Nicholson, Brian K.
The major part of this thesis describes the preparation and reactions of orthomanganated aromatic ketones, such as (1), diagram. Among the new species characterised are substituted acetophenones, analogues of (1), namely: 3,4,5-trimethoxy (3); 4,5,6-trimethoxy (4); 3-t-butyldimethylsiloxy-4,5-dimethoxy (5); 4,5-dimethoxy (6); 5,6-dimethoxy (7); 3-benzyloxy-4,5-dimethoxy (8); and 3-t-butyldimethylsiloxy (9). Hetero aromatic ketones have been used to prepare the corresponding orthomanganated compounds (10), (11), (12), (14) and (15) from the respective ketones 2-acetylthiophene, 3-acetyl-2,5-dimethylthiophene, 2-acetyl-N-methylpyrrole, 3-acetylindole and 2- acetylfuran. The crystal structure of η²-(3-acetyl-2,5-dimethylthien-4-yl)tetracarbonylmanganese (11) has been determined. The 5-manganated derivative (13) of flavanone has also been made. Attempted orthometallations of acetophenones with C₆H₅CH₂Co(CO)₄, C₆H₅CH₂Fe(CO)₂Cp and Pd(OAc)₂ were unsuccessful. Reaction of (4) with Br₂ in carbon tetrachloride gave the orthobromoacetophenone 2'-bromo-3' ,4' ,5'-trimethoxyacetophenone (21) plus [Mn(CO)₄Br]₂. The corresponding orthoiodoacetophenone (28) and [Mn(CO)₄Cl]₂ was obtained using ICl. Other orthohalogenated ketones were obtained similarly. The reactions were sometimes unsuccessful (e.g. for (1)) or complicated (e.g. (5) competitive ring bromination). Oxidation of (1) or (4) with cerium (IV) ammonium nitrate (0.5 mol) in CD₃CO₂D gives the corresponding orthomonodeuterio acetophenones (19) or (20). A by-product from the oxidation of (4), the cyclic hemiketal, (36), was identified by X-ray crystal structure analysis, and one other product, the lactone, (37) was identified spectrally. Determination by ¹H-NMR of the ratio of the 3-deuterio- (1a) to 3-protio- (1) formed in the orthometallation of orthomonodeuterio acetophenone (19) by C₆H₅CH₂Mn(CO)₅ gave a hydrogen isotope effect of 3.6. Similarly, for 2'-deuterio-3' ,4' ,5'-trimethoxyacetophenone (20) the value was 2.9. However, when the orthodeuterioacetophenone (19) was reacted with cis - C₆H₅CH₂Mn(CO)₄P(C₆H₅)₃ the product fac-η²-(2-acetylphenyl) tricarbonyltriphenylphosphinomanganese (16)/(16a) showed a D/H ratio of only 1.1. Implications of these isotope effects for mechanisms are discussed. Reactions of orthomanganted ketones with vinyl reagents in the presence of Pd(II) were studied in two solvents. In methanol, (1) with methyl acrylate (H₂C=CHCOOCH₃) and Li₂PdCl₄ (1 mol) gave methyl E-3-(2-acetylphenyl)acrylate (38). Similarly η²-(2-acetylthien-3-yl)-tetracarbonylmanganese (10) gave methyl E-3-(2-acetylthien-3-yl) acrylate (40). A variety of other products from coupling reactions with vinyl acetate, acrylonitrile, styrene, methyl vinyl ketone, acrolein and allyl alcohol are reported, and possible mechanisms for coupling reactions are discussed. In acetonitrile as solvent, under reflux, with PdCl₂ (1 mol) and excess LiCl, some of the orthomanganated ketones provided new routes to indenes in their reaction with methyl acrylate. Thus (4) gave methyl 3-methyl-5,6,7-trimethoxyindene-2-carboxylate (53), and (2) and (3) gave the corresponding indenes [(51) and (49)]. The thiophene derivative η²-(3-acetyl-2,5-dimethylthien-4-yl)tetracarbonylmanganese (11) also gave the corresponding bicyclic compound, methyl 2,5,6-trimethyl-3H-cyclopenta-[c]-thiophene-4-carboxylate, (54) but the major product was the arylated acrylate ester (55) in this case. In reaction of (2) with HgC1₂ in refluxing methanol, trans-metallation occurs to form chloro(2-acetyl-5-methoxyphenyl)mercury(II) (57). The corresponding mercuric chloride of (1), that is, chloro(2-acetylphenyl)mercury(II) (56), has also been prepared and its crystal structure is reported. In a separate study dodecahydrotriphenylene (C₁₈H₂₄) (58) has been used to prepare the isoelectronic metal arene π-complexes structures η⁶-(C₁₈H₂₄)Cr(CO)₃ (59) and η⁶-(C₁₈H₂₄)Mn(CO)₃⁺ (60). The crystal structures of the former and of the two distinct crystalline modifications of the latter, as BF₄⁻ salts are reported and compared.
Instruction systolic arrays for exact parallel linear algebraic computation
(The University of Waikato, 1988) Krishnamurthy, V.; de Vel, Olivier
This thesis develops new computational algorithms for parallel/distributed error-free (exact) rational (real and complex) computing and its applications to exact linear algebraic computing. The practical realization of these parallel algorithms in VLSI systems using a new concept known as Instruction Systolic Arrays (ISA) is considered. Thus, the thesis represents the author’s contribution to the theory, design, and implementation of parallel/distributed algorithms for exact rational/linear algebraic computing using ISA processors. This thesis consists of six chapters with the following contents. CHAPTER 1 INSTRUCTION SYSTOLIC ARRAYS - A PROGRAMMABLE PARALLEL ARCHITECTURE Chapter 1 introduces the concept of Instruction Systolic arrays (ISA). The ISA is a new versatile programmable parallel architecture that retains all the advantages of systolic arrays. In the ISA, instructions and boolean selectors are pumped through the processing array. The ISA has tremendous potential for VLSI computing because of its ability to execute different types of programs on the same processing array. We also introduce a variant of the ISA known as the Single Instruction Systolic Array (SISA). In the SISA, single instructions and selectors are pumped through the processing array. CHAPTER 2 INSTRUCTION SYSTOLIC ARRAYS FOR DISTRIBUTED CHINESE REMAINDERING/ INTERPOLATION ALGORITHMS We present a parallel/ distributed algorithm for a fundamental problem in Numerical Computing/algebraic computing, namely interpolation and the closely related Chinese remaindering. The ISA implementation of this algorithm is described. A generalization of the interpolation algorithm for multivariable is then presented. The multivariable interpolation algorithm can be realized in a ISA as well as in a pyramid architecture. The Occam simulation of a pyramid for multivariable interpolation is also described. We then present a parallel/ distributed algorithm for rational function interpolation and consider its ISA implementation. CHAPTER 3 PARALLEL MATRIX COMPUTATION USING ISA This chapter introduces a parallel algorithm for the generalized inversion (g-inversion) of matrices, which involves parallel matrix addition and multiplication operations. The ISA implementation of this algorithm is described. The solution of a homogeneous system of linear algebraic equations is based on g-inverse computation and we indicate its ISA implementation. The solution of such equations has important practical applications in finding Petri net invariants, chemical equation balancing and dimensional analysis. Two other important g-inversion algorithms - one iterative and the other direct - are also described. CHAPTER 4 PARALLEL ERROR-FREE RATIONAL ARITHMETIC - ISA IMPLEMENTATION This chapter introduces a new parallel error-free (exact) rational arithmetic system called Parallel Rational Hensel code arithmetic (Para-Hensel code or PHC). We introduce algorithms for parallel element-wise arithmetic operations, and for encoding and decoding PHC codes. We briefly indicate the ISA implementation of these algorithms. We also consider the application of PHC for exact parallel matrix g-inversion with systolic processors. CHAPTER 5 PARALLEL COMPLEX RATIONAL AND MATRIX ARITHMETIC USING GAUSSIAN PRIME CODES In this chapter, we introduce a new parallel exact complex rational arithmetic system based on Gaussian prime codes. Two closely related methods for constructing these codes are described. The first method uses several distinct (multiple) Gaussian primes to construct Gauss-Hensel codes (GHC). The second method uses the powers of one or more Gaussian primes to construct Gauss p-adic codes (GPC). Their practical applications and extension to parallel inversion of complex matrices are described. These systems are amenable for massively parallel realization. CHAPTER 6 ISA - APPLICATIONS TO ARRAY PROCESSING AND REAL-TIME COMPUTING This chapter considers the suitability of the ISA for vector/ array processing computers. We also consider the relationship of the ISA to wavefront processing and dataflow computing. We then describe a linear variant of the ISA known as the Linear ISA (LISA), which is an area efficient architecture. We then briefly indicate some possible application areas of the ISA: real-time robot control applications and high-speed vision systems.
The hormonal control of lipid metabolism in sheep
(The University of Waikato, 1987) Lewis, Kae Jennifer; Molan, Peter C.
The hormonal control of lipid metabolism was investigated by incubation of ovine adipose tissue slices in the presence of hormones the in vitro. The effects of insulin, catecholamines, growth hormone (GH) and insulin-like growth factors (IGFs) on lipogenesis and lipid mobilization were studied to assess their likely individual contributions to overfatness in vivo. From the various measurements of lipid metabolism made, the rates of fatty acid accumulation in the tissue during the incubation were calculated. Since most of the fatty acid released by lipolysis appeared to be re-esterified, observation of glycerol data alone may give a false impression of the extent of fatty acid mobilization or the overall energy balance of the tissue. About 60 - 100% of fatty acid released by lipolysis could be recycled within the tissue, a phenomenon which is under hormonal control and is possibly linked with maintenance of non-shivering thermogenesis. Insulin stimulated the rate of lipogenesis (from acetate) by up to 6-fold, with the average stimulation about 70%, but it failed to affect the rate in tissue from one quarter of the animals tested. Also insulin stimulated the retention of fatty acid by the cell as well as fatty acid recycling, even in tissue in which it was not lipogenic. Thus observation of lipogenesis alone can give a false impression of the lipid-storing effects of a hormone. IGFs, when present at high concentrations, were lipogenic. However, because the binding proteins may restrict the activity of IGFs in vivo, low concentrations of IGF were tested and shown to be lipolytic. It is suggested that whereas the high concentrations of IGFs have been thought to act via the insulin receptor, low concentrations may mediate the lipolytic response via the IGF receptor. Similar states of negative energy balance in the tissue were caused by the presence of either IGF I, IGF II or adrenalin in the medium. GH sometimes stimulated a transient increase in the rate of lipolysis. It is suggested that GH may stimulate the local release of IGF in vitro which then mediates the observed lipolytic activity. GH was also sometimes observed to be lipogenic over the 6 hour incubation period. To investigate the effects of a known physiological change in the animal in vivo on the subsequent effects on lipid metabolism in vitro, GH was administered to animals and their adipose tissue was compared with tissue from control animals. The basal rate of lipogenesis and fat accumulation in vitro was depressed in the bGH-dosed animals as was deposition of fat in vivo. The effectiveness of insulin in increasing lipogenesis in vitro was reduced in the bGH-dosed animals although the percentage response was unaffected. Thus the “lipolytic” effects of exogenous GH may in fact be due to a reduction in lipogenesis, caused by possible post-receptor desensitization of the tissue to the lipogenic effects of insulin as well as to the presence of increased IGF in vivo. Thus the physiological state of the animal can have profound and lasting effects on lipid metabolism in vitro.
A behavioural perspective of visual search and the low prevalence effect
(The University of Waikato, 2024) Hollands, David M.; Perrone, John A.
In visual search, rare items are missed disproportionately often. This Low Prevalence Effect (LPE) is a robust phenomenon with important societal consequences. We asked the question, “Is the schedule of signal presentation controlling eye movements and if so, how?” and hypothesised that visual search is an operant behaviour. To answer this question, we examined the LPE using eye-tracking and incorporated a rich schedule of signal presentation (medium-prevalence condition: 0.50 target probability across 200 trials) and a lean schedule (low-prevalence condition: 0.02 or 0.00 target probability across 1,000 trials) over three experiments. Experiment One was the control, in Experiments Two and Three we increased task difficulty by incorporating a staircase titration procedure, and in Experiment Three we also removed all target-present trials in the low-prevalence condition. We replicated the LPE in all experiments and observed increased levels of searching eye movements throughout the medium-prevalence condition due to an increase in behaviour for the first correct rejection immediately following a correct target-present response which we attribute to the local effects of reinforcement and the strengthening of search behaviour when we find what we are looking for. We also observed that visual attention was being guided towards the densest population of stimulus items (centroid) at the beginning of their search as a search strategy and conclude that this centroid zone is acting as a discriminative stimulus signalling the availability of reinforcement. We contend that eye movements are an operant behaviour controlled by environmental contingencies and reinforcement mechanisms are behind the LPE phenomenon.
A second at the sign: Signage increases visitors’ recall of wildlife information at a kiwi hatchery
(The University of Waikato, 2026) George, Annie Bella; Sargisson, Rebecca
Conservation of wildlife is an integral part of sustainable development of a nation and conservation education needs to remind citizens of how they can play their part. Signs are one of the commonly used low-cost tools to educate the public about different facts and actions necessary to conserve wildlife. I investigated whether a sign increased recall of pecific facts about kiwi predators. I used a single-case, multiple-baseline-across-site design with an ABAB reversal design. At the intervention site The National Kiwi Hatchery, Rotorua, visitor recall increased when the sign was present, compared to when it was absent. At the control site, Hamilton Zoo, where no sign was placed, recall was similar to sign-absent conditions at the intervention site and did not change over the study period. My research provides evidence that signs can be effective low-cost behavioural interventions.