HRV Biofeedback in Neck Pain Effects of Heart Rate Variability Biofeedback in Subjects with Stress-related Chronic Neck Pain: a Pilot study

Abstract Recent studies focusing on autonomic nervous system (ANS) dysfunctions, together with theoretical pathophysiological models of musculoskeletal disorders, indicate the involvement of ANS regulation in development and maintenance of chronic muscle pain. Research has demonstrated the effectiveness of heart rate variability (HRV) biofeedback (BF) in increasing HRV and reducing the symptoms of different disorders characterized by ANS aberration. The study investigated the effects of resonance frequency HRV BF on autonomic regulation and perceived health, pain, stress and disability in 24 subjects with stress-related chronic neckshoulder pain. Twelve subjects participated in 10 weekly sessions of resonant HRV BF and were compared to a control group. Subjective reports and HRV measures during relaxation and in response to a standardized stress protocol were assessed for both groups pre-and postintervention. Group X time interactions revealed a significantly stronger increase over time in perceived health (SF-36) for the treatment group, including vitality, bodily pain and social functioning. Interactions were also seen for HRV during relaxation and reactivity to stress. The present pilot study indicates improvement in perceived health over a 10 week intervention with HRV-biofeedback in subjects with chronic neck-pain. Increased resting HRV as well as enhanced reactivity to hand grip and cold pressor tests might reflect beneficial effects on ANS regulation, and suggest that this intervention protocol is suitable for a larger controlled trial

Weaning of pigs with special focus on the intestinal health

Post weaning diarrhoea (PWD) is a disease affecting pigs world wide. PWD is E. coliassociated but the background is clearly multifactorial. In this work, weaning of piglets was studied with focus on selected faecal microfloras and selected immune functions. However, the work also focused on health status and a model to induce PWD was developed. The work is divided in five separate studies:In the first study, a weaning of healthy piglets was monitored. The phagocyting and killing capacity ofneutrophils in serum was found sufficient from day 6 post partum and these functions were not affected by weaning. Despite absence of diarrhoea, a disturbance ofthe balance in tire coliform flora was observed during the weeks post weaning.In the second study, the influence of feed supplementation with 2500 ppm ZnO was monitored in healthy pigs. The disturbance of the coliform flora due to weaning was reduced.ingle pathogenic strain ofE. coli was monitored. One pathogenic strain ofE. coli was not sufficient to induce PWD. However, challenged pigs displayed a longer period with a disturbed coliform flora titan control pigs. The leukocyte levels increased due to weaning regardless of bacterial challenge. Some immune responses were decreased due to weaning, but the pigs were found capable to mount relevant immune responses. The levels ofthese responses were however not validated.In the fourth study, the influence ofseveral pathogenic strains ofE. coli was monitored. Further, ACTH was given to some groups simulating weaning under stressful conditions. Three pathogenic strains together induced PWD. PWD was also induced by one serotype in connection to shed ofrotavirus. Rotavirus itself did not induce PWD. ACTH was not required to induce PWD, but amplified clinical signs.In the fifth study, different feed related prophylactic measures to prevent PWD were monitored. ZnO-enrichment of feed, meal feed with lactose and dietary fibres; and a probiotic comprising 60 non-pathogenic E. coli-stiains all appeared to have a potential to prevent PWD

Flow boiling heat transfer and pressure drop for zeotropic mixtures in a horizontal tube

Flow boiling heat transfer and pressure drop have been measured in a horizontal tube. The mediums used have been three mixtures of HCFC22 and HCFCI42b, two mixtures of propane and n-butane, and the pure substances HCFC22, HCFCI42b, propane and n-butane. The experimental facility was constructed to resemble a direct expansion evaporator typical for larger heat pumps. The evaporator is 5 metres long and divided into 10 half-metre sections. The results of the measurements show a large decrease in heat transfer during vaporization of mixtures, as compared to the predicted heat transfer using the thermodynamic properties of the mixtures in correlations working well for the pure constituents. The decrease for 50/50% mixtures was about 27- 32% and for 20/80% mixtures 19-24%. The measured heat transfer and pressure drop have been compared with existing correlations from literature (20 for heat transfer and 12 for pressure drop). The correlation most accurately predicting the measured data for pure substances in this paper was the correlation of Klimenko. Including the Thome-Shakir mixture boiling correction factor, the Klimenko correlation also predicted the mixture data with good agreement. For pressure drop, a number of correlations predicted the data well both for pure substances and for mixtures

Flow boiling heat transfer and pressure drop for zeotropic mixtures in a horizontal tube

Flow boiling heat transfer and pressure drop have been measured in a horizontal tube. The mediums used have been three mixtures of HCFC22 and HCFCI42b, two mixtures of propane and n-butane, and the pure substances HCFC22, HCFCI42b, propane and n-butane. The experimental facility was constructed to resemble a direct expansion evaporator typical for larger heat pumps. The evaporator is 5 metres long and divided into 10 half-metre sections. The results of the measurements show a large decrease in heat transfer during vaporization of mixtures, as compared to the predicted heat transfer using the thermodynamic properties of the mixtures in correlations working well for the pure constituents. The decrease for 50/50% mixtures was about 27- 32% and for 20/80% mixtures 19-24%. The measured heat transfer and pressure drop have been compared with existing correlations from literature (20 for heat transfer and 12 for pressure drop). The correlation most accurately predicting the measured data for pure substances in this paper was the correlation of Klimenko. Including the Thome-Shakir mixture boiling correction factor, the Klimenko correlation also predicted the mixture data with good agreement. For pressure drop, a number of correlations predicted the data well both for pure substances and for mixtures