A Method to Measure the Permeability of Dry Fiber Mats

Close to the finalization of the medium density fiberboard process, a fairly thick bed of loosely entangled fibers is compressed in a belt-press to often less than a tenth of its original unstressed thickness. This single unit operation is very important to consider when the manufacturing process of the boards is to be optimized. Despite this, there is a lack of knowledge of the interaction between the fiber mat strength and how the fluid flows through it, i.e. de-aeration. Thus, it is of greatest importance to find reliable methods for studying this stage of the manufacturing process. Following this quest, a method is developed with which the gas permeability of fiber mats can be measured. The method offers the potential to measure the permeability at different flow rates and thus at arbitrary pressure gradients through the material. The method is successfully validated with a porous reference material consisting of polymer spheres, and it is shown that the flow follows Darcy's law at the flow rates of interest. Finally, the method is demonstrated by a presentation of permeability measurements on fiber mats consisting of spruce fibers

Citrullinated histone H3 as a novel prognostic blood marker in patients with advanced cancer

Citrullinated histone H3 (H3Cit) is a central player in the neutrophil release of nuclear chromatin, known as neutrophil extracellular traps (NETs). NETs have been shown to elicit harmful effects on the host, and were recently proposed to promote tumor progression and spread. Here we report significant elevations of plasma H3Cit in patients with advanced cancer compared with age-matched healthy individuals. These elevations were specific to cancer patients as no increase was observed in severely ill and hospitalized patients with a higher non-malignant comorbidity. The analysis of neutrophils from cancer patients showed a higher proportion of neutrophils positive for intracellular H3Cit compared to severely ill patients. Moreover, the presence of plasma H3Cit in cancer patients strongly correlated with neutrophil activation markers neutrophil elastase (NE) and myeloperoxidase (MPO), and the inflammatory cytokines interleukin-6 and -8, known to induce NETosis. In addition, we show that high levels of circulating H3Cit strongly predicted poor clinical outcome in our cohort of cancer patients with a 2-fold increased risk for short-term mortality. Our results also corroborate the association of NE, interleukin-6 and -8 with poor clinical outcome. Taken together, our results are the first to unveil H3Cit as a potential diagnostic and prognostic blood marker associated with an exacerbated inflammatory response in patients with advanced cancer

From permeability modelling to particle deposition in human lung : an overview of activities at the Division of Fluid Mechanics, Luleå University of Technology

Modelling of flow through porous media has been a main research track at the Division of Fluid Mechanics at Luleå University of Technology all since the derivation of Gebart's permeability model in 1992. This model for parallel cylinders has gained great attention and has been extended to flow through perturbed arrays as well as arrays with an arbitrary orientation. Even more, an apparent permeability of an idealized unidirectional reinforcement has been derived for power-law fluid flow perpendicular to the cylinders and the modelling is currently developed for high Reynolds number flow in connection to inner erosion in embankment dams. By usage of Computational Fluid Dynamics (CFD) also more complex structures have been modelled. An example of this is non-crimp fabrics that consists of fibres stitched together in bundles.The two-scale porosity that results is interesting as such but becomes even more fascinating if the impregnating fluid contains particles. It may then happen that the particles are filtrated at the boundaries of the fibre bundles, as visualised by m-PIV, and hence an in-homogenous distribution is obtained. CFD modelling is also introduced for drying of iron ore pellets. In this case heated air is allowed to flow through a bed of green pellets with high water content and the trick is to carry out this procedure without breaking the rather fragile pellets. The flow between the pellets is assumed to be turbulent and it is interesting to know to what extent variations in local flow velocity result in inhomogeneous drying and finally a variation in the properties of the dried and sintered pellets. Work has furthermore been done when dense fibre suspensions are forced to move in pressing of Sheet Moulding Compound. Experimental visualisations yield a complex flow and instead of taking a micromechanical approach inverse modelling is applied with increasing complexity of the rheological model. Recently, a study on the effects upon inhalation of micro- and nano-particles has been launched. A multiply bifurcated asymmetric 3D model, extending from trachea to the segmental bronchi has been developed and initial CFD calculations have been performed. The most critical factor in predicting deposition efficiency is particle size, but flow rate also matters. Information on distribution of deposited particles in every bifurcation unit is provided.Godkänd; 2007; 20080124 (ysko

Corticosteroids in advanced cancer : Epidemiology, symptom relief and patient experiences

Cortisol is the principal circulating glucocorticoid in man and has a wide variety of effects in the body. In advanced metastatic cancer, glucocorticoids are used to alleviate symptoms such as anorexia, poor strength and poor wellbeing. The mechanisms behind the symptom relieving effects are still unclear. The general aim of this thesis was to study endogenous cortisol in patients with advanced cancer and the usage and impact of exogenous corticosteroids in symptom relief. Based on previous findings of impaired control of chemotherapy-related delayed nausea and vomiting in patients receiving single high-doses of dexamethasone, the recovery of the HPA-axis after a single dose of dexamethasone was examined in 10 healthy volunteers and compared with the recovery in 5 patients with gynaecological cancer receiving 8 or 20 mg of dexamethasone in conjunction with platinum-based chemotherapy (paper I). Analyses of urinary cortisol levels showed no differences in the recovery between patients and volunteers, indicating that corticosteroid-induced impairment in the control of delayed nausea was not dependent on the suppression and recovery of the HPA-axis. In an explorative cross-sectional study, urinary cortisol levels were analysed in 23 patients with advanced predominantly gastrointestinal cancer who had rated symptom severity using EORTC QLQ C-30 (paper II). Significant correlations were found between levels of urinary cortisol and more pronounced appetite loss, fatigue and nausea/vomiting. The mean values of urinary cortisol were high, indicating a chronic stress condition in this patient group. Attitudes and practice among physicians regarding treatment with corticosteroids in advanced cancer were examined in two cross-sectional surveys (paper III). The first survey collected answers from 338 physicians. In the second survey, data from 1292 patients enrolled in palliative care were registered. Corticosteroids were used in more than 50 % of the cancer patients and with high response rates when treating appetite loss, nausea, fatigue or poor well-being. The positive response came within the first week and was perceived as persisting beyond four weeks. Few physicians had guidelines on the use of corticosteroids in advanced cancer. Attitudes and examined practice were generally in good agreement with existing evidence. Cortisol production and metabolism was analysed in 13 patients with advanced cancer using high performance liquid chromatography and gas liquid chromatography on 24-hour urine samples (paper IV). Symptom assessments were made with ESAS before and after five days of treatment with 4 mg of betamethasone. Normal cortisol production together with a metabolic shift from cortisone to cortisol in peripheral tissue was seen. This shift was more pronounced in patients with shorter survival, especially in those with an inferior response to corticosteroid treatment. The results support the view of a chronic stress condition and points towards possible interactions between the neuroendocrine system and the immune system in patients with advanced, metastatic cancer. In a prospective observational study, qualitative content analysis was used to study the existential impact of corticosteroid treatment in 10 patients with advanced metastatic cancer (paper V). The patients were interviewed before and after one week of treatment with four milligrams of betamethasone. Prior to treatment patients reported distressing symptoms, deterioration and diminished autonomy, symbolising threat and death. Corticosteroid treatment resulted in enhanced physical abilities and feelings of a more normalized life, symbolising health and hope. This transfer from threat to hope has important existential consequences in the end of life care and should be addressed when communicating goals of treatment and care with the patient and family