Spatial temperature distribution in human hairy and glabrous skin after infrared CO2 laser radiation

<p>Abstract</p> <p>Background</p> <p>CO₂lasers have been used for several decades as an experimental non-touching pain stimulator. The laser energy is absorbed by the water content in the most superficial layers of the skin. The deeper located nociceptors are activated by passive conduction of heat from superficial to deeper skin layers.</p> <p>Methods</p> <p>In the current study, a 2D axial finite element model was developed and validated to describe the spatial temperature distribution in the skin after infrared CO₂laser stimulation. The geometry of the model was based on high resolution ultrasound scans. The simulations were compared to the subjective pain intensity ratings from 16 subjects and to the surface skin temperature distributions measured by an infrared camera.</p> <p>Results</p> <p>The stimulations were sensed significantly slower and less intense in glabrous skin than they were in hairy skin (MANOVA, p < 0.001). The model simulations of superficial temperature correlated with the measured skin surface temperature (r > 0.90, <it>p </it>< 0.001). Of the 16 subjects tested; eight subjects reported pricking pain in the hairy skin following a stimulus of 0.6 J/cm²(5 W, 0.12 s, d1/e²= 11.4 mm) only two reported pain to glabrous skin stimulation using the same stimulus intensity. The temperature at the epidermal-dermal junction (depth 50 μm in hairy and depth 133 μm in glabrous skin) was estimated to 46°C for hairy skin stimulation and 39°C for glabrous skin stimulation.</p> <p>Conclusions</p> <p>As compared to previous one dimensional heat distribution models, the current two dimensional model provides new possibilities for detailed studies regarding CO₂laser stimulation intensity, temperature levels and nociceptor activation.</p

A new self-understanding as chemo sufferer - a phenomenological study of everyday life with chemotherapy induced neuropathy among survivors after colorectal cancer

PURPOSE: To explore the essential meaning of how sensory disturbances caused by Oxaliplatin influence self-understanding and freedom to live an everyday life among survivors after colorectal cancer. METHODS: Data was generated by means of a semi-structured individual interview with eight survivors after colorectal cancer who continued to experience chemotherapy-induced peripheral neuropathy at least one year after completing chemotherapy with Oxaliplatin. Data analysis was guided by existential phenomenology and descriptive life-world research. RESULTS: The essential meaning was structured by four constituents. 1) An unpleasant fluctuating sensation which is impossible to ignore, 2) Breaking through of noise and pain despite struggling to keep them at bay, 3) Continuously feeling ill despite being cured, and 4) Bodily constraints that impact self-understanding and limit enjoyment of life. CONCLUSION: The survivors used distraction to keep the sensory disturbances at bay but were forced to adapt to a new self-understanding as sufferers after chemotherapy despite being cured of their cancer disease. This way of being-in-the-world was understood by survivors, their families and healthcare professionals as a necessary price to pay to be alive. However, marked as sufferer after chemotherapy, the participants’ everyday style of experience and life revealed as an ill health condition, which limited their ability to accomplish everyday activities as before and their freedom to realize their potential—the “I can”

Gamma Oscillations in the Mouse Primary Visual Cortex as an Endophenotype of Schizophrenia

Gamma oscillations (20-50 Hz) are a robust component of brain activity associated with information processing, but are also part of the background spontaneous activity during various brain states including sleep and anesthesia. Our goal was to examine the changes in gamma oscillations that result from pharmacological and genetic manipulations of glutamatergic transmission which produce endophenotypes of schizophrenia. We recorded local field potentials (LFP) and single units through the depth of the mouse primary visual cortex in vivo and examined the alterations in gamma frequency activity under both normal and pathological conditions. Our results indicate that both in awake and anesthetized animals, baseline gamma frequency power in the LFP is increased throughout the cortical lamina, and the signal-to-noise ratio of gamma oscillations produced by a visual stimulus is diminished, most notably in the superficial layers. In addition, the entrainment of single units to the local oscillations in the LFP is reduced in the supragranular (L2/3) and infragranular (L5/6) layers. This work supports the hypothesis that alterations in glutamatergic transmission result in changes to gamma oscillations in primary sensory areas and is consistent with the hypothesis that these changes are associated with disrupted sensory perception

Social foundations of the mathematics curriculum: a rationale for change

The nature of educational aims as criteria for worthwhile curriculum practice is explored and a cross-section of aims for mathematics education is discussed. An aim for mathematics education which emphasises the social aspect of the subject in its being, its conduct and its applications is identified and epistemological foundations for such a view of the nature of the subject are explored. It is argued that such an epistemological perspective of mathematics would be reflected in the social context of the mathematics classroom, arising from a methodology in which the subject would become more problematic and open to change, investigation and hypothesis. The aims of two major mathematics curriculum development projects (the Nuffield Mathematics Project and the School Mathematics Project) are examined to determine the extent to which their aims may take the 'social' nature of mathematics into account. The probable social context of mathematics classrooms using their materials is postulated in an attempt to characterise the nature of the subject as it is reflected in these materials. A view of the nature of mathematics held by practising teachers and by pupils is then established by drawing upon, and extrapolating from, evidence relating to the social context of mathematics classrooms at primary and secondary level. Conclusions follow, which suggest that fundamental change in mathematics education requires, as a first step, the adoption of a new epistemological perspective of the subject in order that the pursuit of the aim which emphasises the social nature of mathematics is achieved. It is suggested that this, in turn, ultimately could lead to the desired balance in the mathematics curriculum which hitherto has been lacking

Teager-kaiser energy operator improves the detection and quantification of nociceptive withdrawal reflexes from surface electromyography

Publication in the conference proceedings of EUSIPCO, Aalborg, Denmark, 201