Bile immunoglobulins and blockage of biliary endoprosthesis: an immunohistochemical study

BACKGROUND: Endoscopic biliary stenting for pancreaticobiliary malignancy is often limited by recurrent stent occlusion as a result of bacterial biofilm formation and sludge deposition. Bile immunoglobulins are thought to be important in combating biliary sepsis. OBJECTIVES: To investigate whether bile immunoglobulins are involved in the pathogenesis of stent blockage. DESIGN: Immunohistochemical technique was used to study the distribution of bile immunoglobulins, bacteria and sludge in blocked biliary stents. METHODS: Patients with malignant obstructive jaundice were palliated by endoscopic insertion of a 10-FG polyethylene stent into the biliary tract. Blocked stents were retrieved from those who presented with recurrent jaundice and fever. The stents were cross-sectionally cut into slices and fixed in formalin. Immunoglobulins were demonstrated by the peroxidase-anti-peroxidase staining procedure using rabbit anti-serum. RESULTS: The central bulk of the stent deposits appeared as an amorphous, structureless material. IgA was found as a rim of dark brown discoloration at the periphery. IgG showed similar distribution and intensity to that of IgA whereas little IgM was detected. CONCLUSIONS: Bile immunoglobulins may facilitate bacterial adhesion, clumping, and hence biofilm formation on the stent surface.     

Evidence for an inhibition by endogenous galanin of neurogenic cutaneous vasodilatation in the pigeon

The effect of high affinity galanin antagonist M35 on neurogenic cutaneous vasodilatation has been studied in the pigeon using a Laser Doppler Imager. Cutaneous application of mustard oil or antidromic electrical stimulation of a cutaneous nerve produced a small increase in skin blood flow. Close arterial injection of M35 prior to chemical or electrical stimulation resulted in a marked augmentation of the vasodilatory response. This effect was abolished by chronic denervation. The results suggest a nerve-mediated inhibitory effect of endogenous galanin on neurogenic cutaneous vasodilatation in the pigeon skin and provide the first experimental evidence for an inhibitory local regulatory function of cutaneous sensory nerves at least in the avian skin.     

Crystal fragmentation and columnar-to-equiaxed transitions in Al-Cu studied by synchrotron X-ray video microscopy

Recent improvements in detectors combined with the eminent brightness and collimation offered with modern synchrotron sources open the way forin situ X-radiographic investigations of solidification fundamentals and phenomena in real alloys at resolutions approaching regular video microscopy. Here, the authors present observations on dendrite fragmentation from columnar fronts in Al-Cu and subsequent transport phenomena. From directional solidification experiments it has been found that the tendency for crystal fragments to detach by remelting of branch roots in the mush dendrite network strongly depends upon the relative buoyant and settling motions of crystal fragments and mush liquid, respectively. At the copper concentrations studied (20 to 30 wt pct), primary aluminum dendrites are lighter than the melt and solidification experiments parallel and anti-parallel to gravity show significant differences in detachment tendency. The experimental results compare well with three different models proposed for fragmentation at different mush locations; however, the results also demonstrate that these models differ substantially both with respect to detachment frequency and the ability for detached fragments to cause eventual columnar to equiaxed transitions. Under particular conditions it has been found that crystal fragmentation could lead to an alternating mesoscale segregation.     

Practical operation strategies for pumped hydroelectric energy storage (PHES) utilising electricity price arbitrage

In this paper, three practical operation strategies (24Optimal, 24Prognostic, and 24Hsitrocial) are compared to the optimum profit feasible for a PHES facility with a 360 MW pump, 300 MW turbine, and a 2 GWh storage utilising price arbitrage on 13 electricity spot markets. The results indicate that almost all (∼97%) of the profits can be obtained by a PHES facility when it is optimised using the 24Optimal strategy developed, which optimises the energy storage based on the day-ahead electricity prices. However, to maximise profits with the 24Optimal strategy, the day-ahead electricity prices must be the actual prices which the PHES facility is charged or the PHES operator must have very accurate price predictions. Otherwise, the predicted profit could be significantly reduced and even become a loss. Finally, using the 24Optimal strategy, the PHES profit can surpass the annual investment repayments required. However, over the 5-year period investigated (2005–2009) the annual profit from the PHES facility varied by more than 50% on five out of six electricity markets considered. Considering the 40-year lifetime of PHES, even with low investment costs, a low interest rate, and a suitable electricity market, PHES is a risky investment without a more predictable profit.     

Centralisation and decentralisation in strategic municipal energy planning in Denmark

Denmark's future energy system is to be entirely based on renewable energy sources. Municipalities will play an important role as local energy planning authorities in terms of adopting and refining this vision in different local contexts. Based on a review of 11 municipal energy plans, this paper examines to what extent municipal energy planning matches national 100% renewable energy strategies. The results indicate a willingness among Danish municipalities to actively carry out energy planning, and the plans reveal a large diversity of (new) activities. At the same time, however, there is a strong need for better coordination of municipal energy planning activities at the central level. It is suggested that the role of municipalities as energy planning authorities needs to be outlined more clearly in, e.g., strategic energy planning which integrates savings, efficiency and renewable energy in all (energy) sectors. This requires the state to provide municipalities with the necessary planning instruments and establish a corresponding planning framework. Consequently, there is a need for a simultaneous centralisation and decentralisation during the implementation of the 100% renewable energy vision. The paper outlines a basic division of tasks between the central and the local level within such a strategic energy planning system.