Pre-sintered zirconia is preferred as a restoration material in dental applications due to its excellent strength and fracture toughness. When abrasive processes were used to obtain the required shape of (Y-TZP) yttria-stabilized tetragonal pre-sintered zirconia, it resulted in material strength degradation in the presence of coolant. Therefore, experiments were carried out on pre-sintered zirconia with diamond grinding wheel to evaluate the performance of cooling conditions such as dry, wet and minimum quantity lubrication (MQL).
View Article and Find Full Text PDFThe application of emulsion for combined heat extraction and lubrication requires continuous monitoring of the quality of emulsion to sustain a desired grinding environment; this is applicable to other grinding fluids as well. Thus to sustain a controlled grinding environment, it is necessary to adopt an effectively lubricated wheel-work interface. The current study was undertaken to assess experimentally the effects of different grinding environments such as dry, minimum quantity lubrication (MQL) and Cryo-MQL on performance, such as grinding force, temperature, surface roughness and chip morphology on Inconel 751, a higher heat resistance material posing thermal problems and wheel loading.
View Article and Find Full Text PDFHemispheric lateralization of hedonic evaluation ('liking') and incentive motivation ('wanting') in neural networks connecting the basal ganglia and insula (BG-I) in humans was examined. Participants with brain damage restricted to the BG-I of the right (n = 5) or left (n = 5) hemisphere, and 26 healthy participants matched on age, sex and intelligence quotient were tested on positively and negatively valenced pictures drawn from varied stimulus categories (Vijayaraghavan et al., 2008).
View Article and Find Full Text PDFDisturbances in cognitive function, particularly memory, are a common complaint of patients with epilepsy. Factors contributing to cognitive dysfunction are the type of epilepsy, type and frequency of seizures, anti-epileptic drugs and the location of underlying brain lesions. Whilst a great deal of attention has been paid to permanent cognitive impairment, the nature and underlying mechanisms of ictal and peri-ictal cognitive changes are poorly understood.
View Article and Find Full Text PDFThis study investigated motivational changes in a 44 year-old man (PJ) who developed considerable reduction in spontaneous activity and speech, flat affect, social withdrawal, loss of interest, inability to "feel," and lack of concern regarding his medical condition after bilateral, focal, anoxic lesions of the globus pallidus. PJ and 30 male controls performed a task designed to parse hedonic evaluation, or liking, from incentive motivation, or wanting. Affective stimuli were presented on a computer screen and subjects controlled viewing time by pressing keys.
View Article and Find Full Text PDFAbulia is the relatively uncommon yet debilitating lack of spontaneous, goal-directed behaviour that is seen predominantly with lesions of the basal ganglia and the frontal lobes. We sought to confirm the existence of abulia as an entity recognized by clinicians, to generate a set of items characteristic of the condition, and to see how clinicians differentiate between overlapping disorders. The Delphi technique was used to survey consultant neurologists and psychiatrists at three hospitals in London.
View Article and Find Full Text PDFA 52 year old lady was admitted for progressive pedal oedema over a six year period and recent onset of hyperpigmentation. Laboratory investigations revealed that she was having a malabsorption syndrome with protein losing enteropathy. In view of associated arthralgia and higher mental function disturbances, a clinical diagnosis of Whipple's disease was postulated.
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