The glutathione-S-transferases (GSTs) (EC.2.5.1.18) are enzymes that participate in cellular detoxification of endogenous as well as foreign electrophilic compounds, function in the cellular detoxification systems and are evolved to protect cells against reactive oxygen metabolites by conjugating the reactive molecules to the nucleophile scavenging tripeptide glutathione (GSH, &amp / #61543 / -glu-cys-gly). The GSTs are found in all eukaryotes and prokaryotic systems, in the cytoplasm, on the microsomes, and in the mitochondria. Cytosolic GSTs have been grouped into seven distinct classes as: alpha (&amp / #61537 / ), mu (&amp / #61549 / ), pi (&amp / #61552 / ), sigma (&amp / #61555 / ), omega, theta (&amp / #61553 / ) and zeta (&amp / #61540 / ). In comparison with other GSTs, class theta enzymes have proven difficult to isolate and characterize. Two distinct theta GSTs have been identified in man, GSTT1-1 and GSTT2-2 three in the rat rGST1-1, rGSTT2-2 and 13-13 and one in the mouse. this study, a class theta GST (GSTT2-2), with high activity towards 1-MS was isolated and purified from bovine liver in 3% yield with a purification factor of 3-fold. The purification protocol included a sequential DEAE cellulose anion exchanger liquid chromatography column, S-hexylglutathione agarose affinity column, dye binding orange A and chromatofocusing columns. The enzyme activity and protein content decreased rapidly after the last step of purification. The purified GSTT2-2 showed significant activity only towards 1-MS as 77 nmole/min/mg. The GSTT2-2 purified from bovine liver had a molecular weigth (Mr) value of about 28,200 which was also confirmed by Western Blott Analysis. The purified farctions of GSTT2-2 with other kolon farctions were tested with anti GSTT2-2, antiGST alfa, antiGST mu and antiGST pi antibodies. The enzyme activities towards CDNB, 4-nitrobenzylchloride (NBC) and 1-menapthyl sulfate were measured as described by Habig and Jacoby.

In the theory of the Behavioral Inhibition System (BIS), Gray and McNaughton (2000) classified events that produce or inhibit goal-directed behaviour into two affective categories: approach versus avoidance. We experience goal-conflict when approximately equal but incompatible approach and avoidance tendencies are concurrently activated. Gray and McNaughton (2000) proposed goal-conflict as a class of mechanisms separable from "simple" mechanisms: Goal-conflict effects are maximal when incompatible approach and avoidance tendencies are balanced, simple effects are maximal when either approach or avoidance tendencies predominate. Gray and McNaughton (2000) saw the hippocampus as a key nexus for resolving goal conflict by recursive amplification of the subjective value of punishment, thereby increasing avoidance tendencies. Rodent hippocampal theta (4-12 Hz) is necessary (but not sufficient) for correct and efficient transmission of hipppocampal outputs. The BIS theory is fundamentally an animal model. It is not clear if a human BIS exists in the same form. Record human hippocampal (4-12 Hz) activity from the scalp is unlikely. However, during goal-conflict resolution, cortically generated theta recorded from the scalp could be modulated by human hippocampal theta. Therefore, superficially recorded 4-12 Hz theta spectra power was used to assess if specific goal-conflict processing activity could be detected in humans. Human goal-conflict processing was assessed in four experiments: the Stop-Signal Task (SST), an existing experimental task, and three variations of a task termed "Choice", created for this thesis. Across experiments, three key conditions were created. Approach and avoidance were balanced in the intermediate condition (maximal goal-conflict). Net approach and avoidance predominated in the adjacent conditions respectively (minimal goal-conflict). Goal-conflict was assessed as the difference between activity in the intermediate condition and the average activity across the adjacent conditions (via extraction of the orthogonal quadratic trend for significance testing). Goal-conflict increased activations consistently at F8, above the right frontal cortex. Increase in task dependent goal-conflict activations were also observed at F7, Fz and F4 above the frontal cortex, and T3, T4, T5 and T6 above the temporal cortex. Activations within the human theta frequency range (4-7 Hz) were consistently detected in the Choice tasks. In the SST, activations spanned the conventional human theta (4-7 Hz) and alpha (8-12 Hz) frequencies. In the Choice tasks, higher conflict theta at T3, T5 and F8 predicted increased avoidance. Taken together, the findings support Gray and McNaugthon�s (2000) views that a) goal-conflict is a class of mechanism separable from simple approach and avoidance; b) goal-conflict processing recruits and increases cortical rhythmic activity within the same frequency range as rodent hippocampal theta (4-12 Hz); and goal-conflict is resolved by increasing the subjective value of punishment, thereby increasing avoidance tendencies. Although speculative, the current work identified a right inferior frontal gyrus neural circuit for slower, and a presupplementary motor area circuit for faster behavioral inhibition during goal-conflict resolution. These circuits are not explicit in the current BIS model.

Anxiety disorder is prevalent and costly. But its diagnosis is underdeveloped and treatment ad hoc. This could be corrected if the neural mechanisms of anxiety were known. All anxiolytic medications produce a decrease in rodent hippocampal theta rhythm - so hippocampal theta could underlie some types of anxiety. But, a review (Chapter 2) showed that ethanol and other anxiolytics increase FM-theta in the human scalp EEG and have other properties unlike hippocampal theta. The experiments in this thesis, therefore, tested for other potential homologues (Chapter 3) of hippocampal theta in the human EEG. The phase of hippocampal theta activity is reset in a working memory task and not an equivalent reference memory task in rats. Furthermore, low doses ethanol increases and high dose ethanol (and other anxiolytics) decrease theta activity. So, EEG was recorded from 15 scalp sites while participants performed non-verbal working memory and reference memory tasks before and after ethanol administration and assessed for the presence of phase-reset and ethanol-related changes in 5-7Hz and 8-11Hz spectral power (chapter 4 and 5). There was little general evidence for stimulus-induced phase-resetting of the ongoing EEG activity (Chapter 6). Increased post-stimulus synchronization in the theta frequency range was accompanied by increases in post-stimulus spectral power - suggesting that the synchronised activity was evoked rather than reset. Across 3 experiments (Chapter 7), low dose ethanol (54.5-146.6[mu]g/l) increased 5-7Hz theta, while the highest dose (307[mu]g/l) reduced task-related-increases in 5-7Hz activity. These effects were noted across electrode locations including frontal-midline sites and particularly at the beginning of the delay period. The suppression of 5-7Hz activity also coincided with an impairment in working memory performance. The dose-response curve for 5-7Hz theta was as predicted from rat hippocampal work. This particular component, linked to high working memory load or task difficulty, is a potential of homologue hippocampal theta. A clear decrease in theta with high dose ethanol, of this type, has not been reported previously. Activity in the 8-11Hz range typically increased with all doses of ethanol. It is clearly not a homologue of hippocampal theta. This is consistent with previous reports of increased alpha with high doses of ethanol - although these have been accompanied by increased, not decreased, theta. There is a potential homologue of hippocampal theta that can be detected in the human EEG (chapter 8); but the observed changes in 5-7Hz activity cannot be localised and may not be related to the hippocampus. It is clear there is more than one type of theta within the human EEG - with opposing sensitivities to ethanol. Critically, these types were detected at a single site and apparently in phase with one another. The current data, together with the previous literature, suggest that theta can be generated concurrently in distinct networks that, under specific task demands, can become coherent and so produce synchonised activity. Future studies need to test higher doses of ethanol and other anxiolytics and use different experimental paradigms to further differentiate the theta systems in the human EEG. Human EEG could be useful for differentiating sub-types of anxiety, and the choice and effectiveness of interventions delivered.

In the theory of the Behavioral Inhibition System (BIS), Gray and McNaughton (2000) classified events that produce or inhibit goal-directed behaviour into two affective categories: approach versus avoidance. We experience goal-conflict when approximately equal but incompatible approach and avoidance tendencies are concurrently activated. Gray and McNaughton (2000) proposed goal-conflict as a class of mechanisms separable from "simple" mechanisms: Goal-conflict effects are maximal when incompatible approach and avoidance tendencies are balanced, simple effects are maximal when either approach or avoidance tendencies predominate. Gray and McNaughton (2000) saw the hippocampus as a key nexus for resolving goal conflict by recursive amplification of the subjective value of punishment, thereby increasing avoidance tendencies. Rodent hippocampal theta (4-12 Hz) is necessary (but not sufficient) for correct and efficient transmission of hipppocampal outputs. The BIS theory is fundamentally an animal model. It is not clear if a human BIS exists in the same form. Record human hippocampal (4-12 Hz) activity from the scalp is unlikely. However, during goal-conflict resolution, cortically generated theta recorded from the scalp could be modulated by human hippocampal theta. Therefore, superficially recorded 4-12 Hz theta spectra power was used to assess if specific goal-conflict processing activity could be detected in humans. Human goal-conflict processing was assessed in four experiments: the Stop-Signal Task (SST), an existing experimental task, and three variations of a task termed "Choice", created for this thesis. Across experiments, three key conditions were created. Approach and avoidance were balanced in the intermediate condition (maximal goal-conflict). Net approach and avoidance predominated in the adjacent conditions respectively (minimal goal-conflict). Goal-conflict was assessed as the difference between activity in the intermediate condition and the average activity across the adjacent conditions (via extraction of the orthogonal quadratic trend for significance testing). Goal-conflict increased activations consistently at F8, above the right frontal cortex. Increase in task dependent goal-conflict activations were also observed at F7, Fz and F4 above the frontal cortex, and T3, T4, T5 and T6 above the temporal cortex. Activations within the human theta frequency range (4-7 Hz) were consistently detected in the Choice tasks. In the SST, activations spanned the conventional human theta (4-7 Hz) and alpha (8-12 Hz) frequencies. In the Choice tasks, higher conflict theta at T3, T5 and F8 predicted increased avoidance. Taken together, the findings support Gray and McNaugthon�s (2000) views that a) goal-conflict is a class of mechanism separable from simple approach and avoidance; b) goal-conflict processing recruits and increases cortical rhythmic activity within the same frequency range as rodent hippocampal theta (4-12 Hz); and goal-conflict is resolved by increasing the subjective value of punishment, thereby increasing avoidance tendencies. Although speculative, the current work identified a right inferior frontal gyrus neural circuit for slower, and a presupplementary motor area circuit for faster behavioral inhibition during goal-conflict resolution. These circuits are not explicit in the current BIS model.

Thesis (Ed. D.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains ix, 88 p. Includes abstract. Includes bibliographical references (p. 70-77).

Thesis (Ph. D.)--University of Chicago, Dept. of Mathematics, June 2000. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--Hanʼguk Oegugŏ Taehakkyo, 1990. / "August 1990." "8"--Spine. Abstract in Korean. Includes bibliographical references (p. 167-173).

Quantum systems in a d-dimensional Hilbert space are considered, where the phase spase is Z(d) x Z(d). An analytic representation in a cell S in the complex plane using Theta functions, is defined. The analytic functions have exactly d zeros in a cell S. The reproducing kernel plays a central role in this formalism. Wigner and Weyl functions are also studied. Quantum systems with positions in a circle S and momenta in Z are also studied. An analytic representation in a strip A in the complex plane is also defined. Coherent states on a circle are studied. The reproducing kernel is given. Wigner and Weyl functions are considered.

The medial temporal lobe (MTL) is crucial for episodic and spatial memory, and shows rhythmicity in the local field potential and neuronal spiking. Gamma oscillations (>40Hz) are mediatepd by local circuitry and interact with slower theta oscillations (6-10 Hz). Both oscillation frequencies are modulated by cholinergic input from the medial septum. Entorhinal grid cells fire when an animal visits particular locations in the environment arranged on the corners of tightly packed, equilateral triangles. Grid cells show phase precession, in which neurons fire at progressively earlier phases relative to theta oscillation as animals move through firing fields. This work focuses on the temporal organization of spiking and network rhythms, and their modulation by septal inputs, which are thought to be involved in MTL function. First, I recorded grid cells as rats explored open spaces and examined precession, previously only characterized on linear tracks, and compared it to predictions from models. I identified precession, including in conjunctive head-direction-by-grid cells and on passes that clipped the edge of the firing field. Secondly, I studied problems of measuring single neuron theta rhythmicity and developed an improved approach. Using the novel approach, I identified diverse modulation of rat medial entorhinal neurons’ rhythmic frequencies by running speed, independent from the modulation of firing rate by speed. Under pharmacological inactivation of the septum, rhythmic tuning was disrupted while rate tuning was enhanced. The approach also showed that available data is insufficient to prove that bat grid cells are arrhythmic due to low firing rates. In the final project, I optogenetically silenced cholinergic septal cells while recording from hippocampal area CA1. I identified changes in theta rhythmic currents and in theta-gamma coupling. This silencing disrupted performance when applied during the encoding phase of a delayed match to position task. These data support hypothetical roles of these rhythms in encoding and retrieval and suggest possible mechanisms for their modulation. Together, evidence from these projects suggests a role for theta in the function of spatial and episodic memory. These oscillations have important implications for communication and computation, and they can provide a substrate for efficient brain function.

Neste trabalho, com base em representações por matrizes de duas linhas para alguns tipos de partição (algumas já conhecidas e outras novas), identificamos propriedades sugeridas por classificá-las de acordo com a soma dos elementos de sua segunda linha. Esta soma sempre fornece alguma propriedade da partição relacionada. Se considerarmos versões sem sinal de algumas funções Mock Theta, seu termo geral pode ser interpretado como função geradora para algum tipo de partição com restrições. Para retornar aos coeficientes originais, é possível definir um peso para cada matriz e depois somá-las para contá-los. Uma representação análoga para essas partições nos permite observar propriedades sobre elas, novamente por meio de uma classificação referente à soma dos seu elementos da segunda linha. Esta seriação é feita por meio de tabelas criadas pelo software matemático Maple, as quais nos sugerem padrões e identidades relacionadas com outros tipos de partições conhecidas e, muitas vezes, encontrando uma fórmula fechada para contá-las. Tendo as conjecturas obtidas, elas são provadas por meio de bijeções entre conjuntos ou por contagem. / In this work, based on representations by matrices of two lines for some kind of partition (some already known and other new ones), we identify properties suggested by classifying them according to the sum of its second line. This sum always provides some properties of the related partition. If we consider unsigned versions of some Mock Theta Functions, its general term can be interpreted as generating function for some kind of partition with restrictions. To come back to the original coefficients, you can set a weight for each array and so add them to evaluate the coefficients. An analogous representation for partitions allows us to observe properties, again by classificating them according to the sum of its elements on the second row. This classification is made by means of tables created by mathematical software Maple, which suggest patterns, identities related to other known types of partitions and often, finding a closed formula to count them. Having established conjectured identities, all are proved by bijections between sets or counting methods.